diff --git a/src/components/modelAlias/ModelMappingDiagram.module.scss b/src/components/modelAlias/ModelMappingDiagram.module.scss
index 561a2c2..20c3194 100644
--- a/src/components/modelAlias/ModelMappingDiagram.module.scss
+++ b/src/components/modelAlias/ModelMappingDiagram.module.scss
@@ -7,6 +7,16 @@
   -webkit-overflow-scrolling: touch;
 }
 
+.tapHint {
+  position: sticky;
+  left: 0;
+  z-index: 3;
+  font-size: 12px;
+  color: var(--text-secondary);
+  padding: 0 4px;
+  margin-bottom: 8px;
+}
+
 .container {
   display: inline-flex;
   position: relative;
@@ -100,6 +110,12 @@
     border-color: var(--primary-color);
     border-width: 2px;
   }
+
+  &.selected {
+    border-color: var(--primary-color);
+    background-color: var(--bg-secondary);
+    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
+  }
 }
 
 // Mindmap-style provider branch (root node)
diff --git a/src/components/modelAlias/ModelMappingDiagram.tsx b/src/components/modelAlias/ModelMappingDiagram.tsx
index 57906d9..209a181 100644
--- a/src/components/modelAlias/ModelMappingDiagram.tsx
+++ b/src/components/modelAlias/ModelMappingDiagram.tsx
@@ -62,6 +62,13 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
   const { t } = useTranslation();
   const resolvedTheme = useThemeStore((state) => state.resolvedTheme);
   const isDark = resolvedTheme === 'dark';
+  const enableTapLinking = useMemo(() => {
+    if (typeof window === 'undefined' || typeof window.matchMedia === 'undefined') return false;
+    return (
+      window.matchMedia('(any-pointer: coarse)').matches &&
+      !window.matchMedia('(any-pointer: fine)').matches
+    );
+  }, []);
   
   const containerRef = useRef<HTMLDivElement>(null);
   const [lines, setLines] = useState<DiagramLine[]>([]);
@@ -69,6 +76,8 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
   const [draggedAlias, setDraggedAlias] = useState<string | null>(null);
   const [dropTargetAlias, setDropTargetAlias] = useState<string | null>(null);
   const [dropTargetSource, setDropTargetSource] = useState<string | null>(null);
+  const [tapSourceId, setTapSourceId] = useState<string | null>(null);
+  const [tapAlias, setTapAlias] = useState<string | null>(null);
   const [extraAliases, setExtraAliases] = useState<string[]>([]);
   const [contextMenu, setContextMenu] = useState<ContextMenuState | null>(null);
   const [collapsedProviders, setCollapsedProviders] = useState<Set<string>>(new Set());
@@ -301,16 +310,18 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
   // Drag and Drop handlers
   // 1. Source -> Alias
   const handleDragStart = (e: DragEvent, source: SourceNode) => {
+    setTapSourceId(null);
+    setTapAlias(null);
     setDraggedSource(source);
     e.dataTransfer.setData('text/plain', source.id);
     e.dataTransfer.effectAllowed = 'link';
   };
 
   const handleDragOver = (e: DragEvent, alias: string) => {
+    if (!draggedSource || draggedSource.aliases.some((entry) => entry.alias === alias)) return;
     e.preventDefault(); // Allow drop
-    if (draggedSource && !draggedSource.aliases.some((entry) => entry.alias === alias)) {
-      setDropTargetAlias(alias);
-    }
+    e.dataTransfer.dropEffect = 'link';
+    setDropTargetAlias(alias);
   };
 
   const handleDragLeave = () => {
@@ -328,16 +339,18 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
 
   // 2. Alias -> Source
   const handleDragStartAlias = (e: DragEvent, alias: string) => {
+    setTapSourceId(null);
+    setTapAlias(null);
     setDraggedAlias(alias);
     e.dataTransfer.setData('text/plain', alias);
     e.dataTransfer.effectAllowed = 'link';
   };
 
   const handleDragOverSource = (e: DragEvent, source: SourceNode) => {
+    if (!draggedAlias || source.aliases.some((entry) => entry.alias === draggedAlias)) return;
     e.preventDefault();
-    if (draggedAlias && !source.aliases.some((entry) => entry.alias === draggedAlias)) {
-      setDropTargetSource(source.id);
-    }
+    e.dataTransfer.dropEffect = 'link';
+    setDropTargetSource(source.id);
   };
 
   const handleDragLeaveSource = () => {
@@ -382,6 +395,45 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
     [providerNodes]
   );
 
+  const handleTapSelectSource = (source: SourceNode) => {
+    if (!onUpdate) return;
+    if (tapSourceId === source.id) {
+      setTapSourceId(null);
+      return;
+    }
+
+    if (tapAlias) {
+      onUpdate(source.provider, source.name, tapAlias);
+      setTapSourceId(null);
+      setTapAlias(null);
+      return;
+    }
+
+    setTapSourceId(source.id);
+    setTapAlias(null);
+  };
+
+  const handleTapSelectAlias = (alias: string) => {
+    if (!onUpdate) return;
+    if (tapAlias === alias) {
+      setTapAlias(null);
+      return;
+    }
+
+    if (tapSourceId) {
+      const source = resolveSourceById(tapSourceId);
+      if (source) {
+        onUpdate(source.provider, source.name, alias);
+      }
+      setTapSourceId(null);
+      setTapAlias(null);
+      return;
+    }
+
+    setTapAlias(alias);
+    setTapSourceId(null);
+  };
+
   const handleUnlinkSource = (provider: string, sourceModel: string, alias: string) => {
     if (onDeleteLink) onDeleteLink(provider, sourceModel, alias);
   };
@@ -459,6 +511,9 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
 
   return (
     <div className={[styles.scrollContainer, className].filter(Boolean).join(' ')}>
+      {enableTapLinking && onUpdate && (
+        <div className={styles.tapHint}>{t('oauth_model_alias.diagram_tap_hint')}</div>
+      )}
       <div
         className={styles.container}
         ref={containerRef}
@@ -480,15 +535,15 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
         </svg>
 
         <ProviderColumn
-        providerNodes={providerNodes}
-        collapsedProviders={collapsedProviders}
-        getProviderColor={getProviderColor}
-        providerGroupHeights={providerGroupHeights}
-        providerRefs={providerRefs}
-        onToggleCollapse={toggleProviderCollapse}
-        onContextMenu={(e, type, data) => handleContextMenu(e, type, data)}
-        label={t('oauth_model_alias.diagram_providers')}
-        expandLabel={t('oauth_model_alias.diagram_expand')}
+          providerNodes={providerNodes}
+          collapsedProviders={collapsedProviders}
+          getProviderColor={getProviderColor}
+          providerGroupHeights={providerGroupHeights}
+          providerRefs={providerRefs}
+          onToggleCollapse={toggleProviderCollapse}
+          onContextMenu={(e, type, data) => handleContextMenu(e, type, data)}
+          label={t('oauth_model_alias.diagram_providers')}
+          expandLabel={t('oauth_model_alias.diagram_expand')}
           collapseLabel={t('oauth_model_alias.diagram_collapse')}
         />
         <SourceColumn
@@ -496,6 +551,8 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
           collapsedProviders={collapsedProviders}
           sourceRefs={sourceRefs}
           getProviderColor={getProviderColor}
+          selectedSourceId={enableTapLinking ? tapSourceId : null}
+          onSelectSource={enableTapLinking ? handleTapSelectSource : undefined}
           draggedSource={draggedSource}
           dropTargetSource={dropTargetSource}
           draggable={!!onUpdate}
@@ -515,6 +572,8 @@ export const ModelMappingDiagram = forwardRef<ModelMappingDiagramRef, ModelMappi
           aliasRefs={aliasRefs}
           dropTargetAlias={dropTargetAlias}
           draggedAlias={draggedAlias}
+          selectedAlias={enableTapLinking ? tapAlias : null}
+          onSelectAlias={enableTapLinking ? handleTapSelectAlias : undefined}
           draggable={!!onUpdate}
           onDragStart={handleDragStartAlias}
           onDragEnd={() => {
diff --git a/src/components/modelAlias/ModelMappingDiagramColumns.tsx b/src/components/modelAlias/ModelMappingDiagramColumns.tsx
index 69e4244..bd8f04b 100644
--- a/src/components/modelAlias/ModelMappingDiagramColumns.tsx
+++ b/src/components/modelAlias/ModelMappingDiagramColumns.tsx
@@ -85,6 +85,8 @@ interface SourceColumnProps {
   collapsedProviders: Set<string>;
   sourceRefs: RefObject<Map<string, HTMLDivElement>>;
   getProviderColor: (provider: string) => string;
+  selectedSourceId?: string | null;
+  onSelectSource?: (source: SourceNode) => void;
   draggedSource: SourceNode | null;
   dropTargetSource: string | null;
   draggable: boolean;
@@ -102,6 +104,8 @@ export function SourceColumn({
   collapsedProviders,
   sourceRefs,
   getProviderColor,
+  selectedSourceId,
+  onSelectSource,
   draggedSource,
   dropTargetSource,
   draggable,
@@ -134,7 +138,10 @@ export function SourceColumn({
             }}
             className={`${styles.item} ${styles.sourceItem} ${
               draggedSource?.id === source.id ? styles.dragging : ''
-            } ${dropTargetSource === source.id ? styles.dropTarget : ''}`}
+            } ${dropTargetSource === source.id ? styles.dropTarget : ''} ${
+              selectedSourceId === source.id ? styles.selected : ''
+            }`}
+            onClick={() => onSelectSource?.(source)}
             draggable={draggable}
             onDragStart={(e) => onDragStart(e, source)}
             onDragEnd={onDragEnd}
@@ -169,6 +176,8 @@ interface AliasColumnProps {
   aliasRefs: RefObject<Map<string, HTMLDivElement>>;
   dropTargetAlias: string | null;
   draggedAlias: string | null;
+  selectedAlias?: string | null;
+  onSelectAlias?: (alias: string) => void;
   draggable: boolean;
   onDragStart: (e: DragEvent, alias: string) => void;
   onDragEnd: () => void;
@@ -184,6 +193,8 @@ export function AliasColumn({
   aliasRefs,
   dropTargetAlias,
   draggedAlias,
+  selectedAlias,
+  onSelectAlias,
   draggable,
   onDragStart,
   onDragEnd,
@@ -212,7 +223,10 @@ export function AliasColumn({
           }}
           className={`${styles.item} ${styles.aliasItem} ${
             dropTargetAlias === node.alias ? styles.dropTarget : ''
-          } ${draggedAlias === node.alias ? styles.dragging : ''}`}
+          } ${draggedAlias === node.alias ? styles.dragging : ''} ${
+            selectedAlias === node.alias ? styles.selected : ''
+          }`}
+          onClick={() => onSelectAlias?.(node.alias)}
           draggable={draggable}
           onDragStart={(e) => onDragStart(e, node.alias)}
           onDragEnd={onDragEnd}
diff --git a/src/i18n/locales/en.json b/src/i18n/locales/en.json
index 82f948e..e6155e3 100644
--- a/src/i18n/locales/en.json
+++ b/src/i18n/locales/en.json
@@ -577,6 +577,7 @@
     "diagram_settings_title": "Alias settings — {{alias}}",
     "diagram_settings_source_title": "Source model settings",
     "diagram_settings_empty": "No mappings for this alias yet.",
+    "diagram_tap_hint": "On touch devices: tap a source model, then tap an alias to link.",
     "view_mode": "View mode",
     "view_mode_diagram": "Diagram",
     "view_mode_list": "List",
diff --git a/src/i18n/locales/zh-CN.json b/src/i18n/locales/zh-CN.json
index c748757..10f85c6 100644
--- a/src/i18n/locales/zh-CN.json
+++ b/src/i18n/locales/zh-CN.json
@@ -577,6 +577,7 @@
     "diagram_settings_title": "别名设置 — {{alias}}",
     "diagram_settings_source_title": "源模型设置",
     "diagram_settings_empty": "该别名暂无映射。",
+    "diagram_tap_hint": "触摸设备上：先点选源模型，再点选别名即可建立映射。",
     "view_mode": "视图模式",
     "view_mode_diagram": "概览",
     "view_mode_list": "管理",