diff --git a/gamewindow.ui b/gamewindow.ui
index 48d19d09..cdd18bfa 100644
--- a/gamewindow.ui
+++ b/gamewindow.ui
@@ -319,6 +319,7 @@
      <string>算法(&amp;A)</string>
     </property>
     <addaction name="actionIDS_I"/>
+    <addaction name="actionDepthExtension_D"/>
    </widget>
    <addaction name="menu_F"/>
    <addaction name="menu_C"/>
@@ -1235,6 +1236,17 @@
     <string>迭代加深(&amp;I)</string>
    </property>
   </action>
+  <action name="actionDepthExtension_D">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="checked">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>深度延伸(&amp;D)</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <customwidgets>
diff --git a/include/config.h b/include/config.h
index 72403f51..382fd48d 100644
--- a/include/config.h
+++ b/include/config.h
@@ -78,12 +78,6 @@
 
 #define SORT_MOVE_WITH_HUMAN_KNOWLEDGES
 
-//#define DEAL_WITH_HORIZON_EFFECT
-
-#ifdef DEAL_WITH_HORIZON_EFFECT
-#define HORIZON_EFFECT_ONLY_ONE_MOVE
-#endif
-
 //#define IDS_WINDOW
 //#define IDS_DEBUG
 //#define IDS_ADD_VALUE
diff --git a/src/ai/search.cpp b/src/ai/search.cpp
index d6a24f24..4ff1bee8 100644
--- a/src/ai/search.cpp
+++ b/src/ai/search.cpp
@@ -863,17 +863,11 @@ value_t AIAlgorithm::search(depth_t depth, value_t alpha, value_t beta, Node *no
 
         doMove(node->children[i]->move);
 
-#ifdef DEAL_WITH_HORIZON_EFFECT
-        if (false
-#ifdef HORIZON_EFFECT_ONLY_ONE_MOVE
-            || nchild == 1
-#endif // HORIZON_EFFECT_ONLY_ONE_MOVE
-            ) {
+        if (gameOptions.getDepthExtension() == true && nchild == 1) {
             epsilon = 1;
         } else {
             epsilon = 0;
         }
-#endif // DEAL_WITH_HORIZON_EFFECT
 
 #ifdef DEEPER_IF_ONLY_ONE_LEGAL_MOVE
         if (node->childrenSize == 1) {
diff --git a/src/game/option.cpp b/src/game/option.cpp
index 7310523f..a8c8a559 100644
--- a/src/game/option.cpp
+++ b/src/game/option.cpp
@@ -88,3 +88,15 @@ bool Options::getIDSEnabled()
 {
     return IDSEnabled;
 }
+
+// DepthExtension
+
+void Options::setDepthExtension(bool enabled)
+{
+    depthExtension = enabled;
+}
+
+bool Options::getDepthExtension()
+{
+    return depthExtension;
+}
diff --git a/src/game/option.h b/src/game/option.h
index 71ef695f..78351974 100644
--- a/src/game/option.h
+++ b/src/game/option.h
@@ -43,6 +43,10 @@ public:
     void setIDSEnabled(bool enabled);
     bool getIDSEnabled();
 
+    // DepthExtension
+    void setDepthExtension(bool enabled);
+    bool getDepthExtension();
+
 protected:
 
 private:
@@ -67,6 +71,9 @@ private:
 
     // Alpha-Beta 搜索时是否迭代加深
     bool IDSEnabled { false };
+
+    // DepthExtension
+    bool depthExtension {true};
 };
 
 extern Options gameOptions;
diff --git a/src/ui/qt/gamecontroller.cpp b/src/ui/qt/gamecontroller.cpp
index c9ecedf6..30c7de80 100644
--- a/src/ui/qt/gamecontroller.cpp
+++ b/src/ui/qt/gamecontroller.cpp
@@ -437,6 +437,12 @@ void GameController::setIDS(bool enabled)
     gameOptions.setIDSEnabled(enabled);
 }
 
+// DepthExtension
+void GameController::setDepthExtension(bool enabled)
+{
+    gameOptions.setDepthExtension(enabled);
+}
+
 // 上下翻转
 void GameController::flip()
 {
diff --git a/src/ui/qt/gamecontroller.h b/src/ui/qt/gamecontroller.h
index c4220eb3..40ea68f6 100644
--- a/src/ui/qt/gamecontroller.h
+++ b/src/ui/qt/gamecontroller.h
@@ -180,6 +180,9 @@ public slots:
     // Alpha-Beta 搜索时是否迭代加深
     void setIDS(bool enabled);
 
+    // DepthExtension
+    void setDepthExtension(bool enabled);
+
     // 上下翻转
     void flip();
 
diff --git a/src/ui/qt/gamewindow.cpp b/src/ui/qt/gamewindow.cpp
index d8b65dff..55597713 100644
--- a/src/ui/qt/gamewindow.cpp
+++ b/src/ui/qt/gamewindow.cpp
@@ -245,6 +245,10 @@ void MillGameWindow::initialize()
     connect(ui.actionIDS_I, SIGNAL(toggled(bool)),
             gameController, SLOT(setIDS(bool)));
 
+    // DepthExtension
+    connect(ui.actionDepthExtension_D, SIGNAL(toggled(bool)),
+            gameController, SLOT(setDepthExtension(bool)));
+
     // 视图上下翻转
     connect(ui.actionFlip_F, &QAction::triggered,
             gameController, &GameController::flip);