diff --git a/NineChess/src/MemoryPool.h b/NineChess/src/MemoryPool.h
index bae976ea..78488371 100644
--- a/NineChess/src/MemoryPool.h
+++ b/NineChess/src/MemoryPool.h
@@ -75,7 +75,7 @@ class MemoryPool
   private:
     union Slot_ {
       value_type element;
-      Slot_* next;
+      union Slot_* next;
     };
 
     typedef char* data_pointer_;
diff --git a/NineChess/src/config.h b/NineChess/src/config.h
index 4e42a325..0c96cbda 100644
--- a/NineChess/src/config.h
+++ b/NineChess/src/config.h
@@ -25,6 +25,8 @@
 
 #define RANDOM_MOVE
 
+#define MILL_FIRST
+
 //#define DEAL_WITH_HORIZON_EFFECT
 
 #define IDS_SUPPORT
diff --git a/NineChess/src/ninechess.cpp b/NineChess/src/ninechess.cpp
index 5d2753e0..d824f0d1 100644
--- a/NineChess/src/ninechess.cpp
+++ b/NineChess/src/ninechess.cpp
@@ -1625,11 +1625,11 @@ bool NineChess::win(bool forceDraw)
     return false;
 }
 
-int NineChess::isInMills(int pos)
+int NineChess::isInMills(int pos, bool test)
 {
     int n = 0;
     int pos1, pos2;
-    char m = board_[pos] & '\x30';
+    char m = test? INT32_MAX : board_[pos] & '\x30';
     for (int i = 0; i < 3; i++) {
         pos1 = millTable[pos][i][0];
         pos2 = millTable[pos][i][1];
diff --git a/NineChess/src/ninechess.h b/NineChess/src/ninechess.h
index 443de547..60d5fe11 100644
--- a/NineChess/src/ninechess.h
+++ b/NineChess/src/ninechess.h
@@ -475,7 +475,7 @@ public:
 
 protected:
     // 判断棋盘pos处的棋子处于几个“三连”中
-    int isInMills(int pos);
+    int isInMills(int pos, bool test = false);
 
     // 判断玩家的所有棋子是否都处于“三连”状态
     bool isAllInMills(char ch);
diff --git a/NineChess/src/ninechessai_ab.cpp b/NineChess/src/ninechessai_ab.cpp
index 4816b856..5c554590 100644
--- a/NineChess/src/ninechessai_ab.cpp
+++ b/NineChess/src/ninechessai_ab.cpp
@@ -153,7 +153,16 @@ struct NineChessAi_ab::Node *NineChessAi_ab::addNode(
     if (parent) {
         // 若没有启用置换表，或启用了但为叶子节点，则 bestMove 为0
         if (bestMove == 0 || move != bestMove) {
+#ifdef MILL_FIRST
+            // 优先成三
+            if (chessTemp.getStage() == NineChess::GAME_PLACING && move > 0 && chessTemp.isInMills(move, true)) {
+                parent->children.insert(parent->children.begin(), newNode);
+            } else {
+                parent->children.push_back(newNode);
+            }
+#else
             parent->children.push_back(newNode);
+#endif
         } else {
             // 如果启用了置换表并且不是叶子结点，把哈希得到的最优着法换到首位
             parent->children.insert(parent->children.begin(), newNode);