diff --git a/src/ai/movegen.cpp b/src/ai/movegen.cpp
index c31c8c18..b9dcbd91 100644
--- a/src/ai/movegen.cpp
+++ b/src/ai/movegen.cpp
@@ -51,10 +51,12 @@ void MoveList::generate(AIAlgorithm &ai, Game &tempGame,
             for (move_t i : movePriorityTable) {
                 square = static_cast<square_t>(i);
 
+                // 如果已经有子占据, 继续检索
                 if (tempGame.boardLocations[square]) {
                     continue;
                 }
 
+                // 否则如果是空位
                 if (tempGame.position.phase != PHASE_READY || node != root) {
                     ai.addNode(node, VALUE_ZERO, (move_t)square, bestMove, tempGame.position.sideToMove);
                 } else {
diff --git a/src/ai/search.cpp b/src/ai/search.cpp
index 8740e5da..2baeaad7 100644
--- a/src/ai/search.cpp
+++ b/src/ai/search.cpp
@@ -220,11 +220,18 @@ struct AIAlgorithm::Node *AIAlgorithm::addNode(
         // 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 // TODO: Adapt MEMORY_POOL
-            if (tempGame.getPhase() == GAME_PLACING && move > 0 && tempGame.position.board.isInMills(move, true)) {
-                parent->children.insert(parent->children.begin(), newNode);
+            // 优先成三
+            if (tempGame.getPhase() == PHASE_PLACING && move > 0 &&
+                tempGame.position.board.inHowManyMills2((square_t)move)) {
+                int pcs = parent->childrenSize;
+                for (int i = pcs; i >= 1; i--) {
+                    parent->children[i] = parent->children[i - 1];
+                }
+                parent->children[0] = newNode;
+                parent->childrenSize++;
             } else {
-                parent->children.push_back(newNode);
+                parent->children[parent->childrenSize] = newNode;
+                parent->childrenSize++;
             }
 #else // MILL_FIRST
             parent->children[parent->childrenSize] = newNode;
diff --git a/src/game/board.cpp b/src/game/board.cpp
index 3a560284..a7ab609f 100644
--- a/src/game/board.cpp
+++ b/src/game/board.cpp
@@ -225,6 +225,22 @@ int Board::inHowManyMills(square_t square)
     return n;
 }
 
+int Board::inHowManyMills2(square_t square)
+{
+    int n = 0;
+    int square_1, square_2;
+
+    for (int l = 0; l < LINE_TYPES_COUNT; l++) {
+        square_1 = millTable[square][l][0];
+        square_2 = millTable[square][l][1];
+        if (locations[square_1] & locations[square_2]) {
+            n++;
+        }
+    }
+
+    return n;
+}
+
 int Board::addMills(square_t square)
 {
     // 成三用一个64位整数了，规则如下
diff --git a/src/game/board.h b/src/game/board.h
index 0a0f4420..98ac3040 100644
--- a/src/game/board.h
+++ b/src/game/board.h
@@ -70,6 +70,7 @@ public:
 
     // 判断棋盘 square 处的棋子处于几个“三连”中
     int inHowManyMills(square_t square);
+    int inHowManyMills2(square_t square);
 
     // 判断玩家的所有棋子是否都处于“三连”状态
     bool isAllInMills(player_t);