diff --git a/AquaMai/RenderTweak/SlideAutoPlayTweak.cs b/AquaMai/RenderTweak/SlideAutoPlayTweak.cs
new file mode 100644
index 00000000..17017b6f
--- /dev/null
+++ b/AquaMai/RenderTweak/SlideAutoPlayTweak.cs
@@ -0,0 +1,102 @@
+using System.Collections.Generic;
+using HarmonyLib;
+using Manager;
+using Monitor;
+
+namespace AquaMai.RenderTweak;
+
+public class SlideAutoPlayTweak
+{
+    /* 这个 Patch 用于修复以下 bug:
+     *     SlideFan 在 AutoPlay 时, 只有第一个箭头会消失
+     * 原 method 逻辑如下:
+     * 
+     *     if (this.IsNoteCheckTimeStartIgnoreJudgeWait())
+     *     {
+     *         // do something ...
+     *         if (!GameManager.IsAutoPlay())
+     *         {
+     *             // do something ...
+     *             for (int index = 0; index < this._arrowPrefubs.Length && (double) index < (double) num2 * 11.0; ++index)
+     *             {
+     *                 // do something about displaying arrows ...
+     *             }
+     *         }
+     *         else
+     *         {
+     *             float num4 = (currentMsec - this.StarLaunchMsec) / (this.StarArriveMsec - this.StarLaunchMsec - this.lastWaitTime);
+     *             for (int index = 0; index < this._arrowPrefubs.Length && (double) index < (double) num4 * 1.0; ++index)
+     *             {
+     *                 // do something about displaying arrows ...
+     *             }
+     *             if ((double) num4 > 1.0)
+     *                 num1 = 3;
+     *         }
+     *         // do something ...
+     *     }
+     * 
+     * 导致这个 bug 的原因是 else 分支的 for 循环终止条件写错了, 应该是 11.0 (因为有 11 个箭头), SBGA 写成了 1.0
+     * 这个 method 中一共只有 5 处 ldc.r4 的 IL Code, 依次为 10.0, 11.0, 1.0, 1.0, 0.0
+     * 修复 bug 需要把第三处的 1.0 更改为 11.0, 这里使用 Transpiler 解决
+     */
+    [HarmonyTranspiler]
+    [HarmonyPatch(typeof(SlideFan), "NoteCheck")]
+    private static IEnumerable<CodeInstruction> FixFanAutoPlayArrow(IEnumerable<CodeInstruction> instructions)
+    {
+        List<CodeInstruction> instList = new List<CodeInstruction>(instructions);
+        bool found = false;
+        for (int i = 0; i < instList.Count; i++)
+        {
+            CodeInstruction inst = instList[i];
+            if (inst.LoadsConstant(11.0))
+            {
+                found = true;
+            }
+
+            if (found && inst.LoadsConstant(1.0))
+            {
+                inst.operand = 11.0f;
+                break;
+            }
+        }
+        return instList;
+    }
+    
+    /* 这个 Patch 让 Slide 在 AutoPlay 的时候, 每个区仍然会分按下和松开两段进行推进 (加上 this._hitIn 的变化)
+     * 原 method 逻辑如下:
+     *
+     *     if (!GameManager.IsAutoPlay())
+     *     {
+     *         // do somethings ...
+     *     }
+     *     else
+     *     {
+     *         float num1 = (currentMsec - this.StarLaunchMsec) / (this.StarArriveMsec - this.StarLaunchMsec - this.lastWaitTime);
+     *         this._hitIndex = (int) ((double) this._hitAreaList.Count * (double) num1);
+     *         if (this._hitIndex >= this._hitAreaList.Count)
+     *             this._hitIndex = this._hitAreaList.Count - 1;
+     *         if (this._hitIndex < 0)
+     *             this._hitIndex = 0;
+     *         int num2 = (int) ((double) this._dispLaneNum * this.GetDeleteArrowDistance());
+     *         // do somethings ...
+     *     }
+     *
+     * 现在要在 this.GetDeleteArrowDistance() 之前插入
+     *     this._hitIn = ((float)this._hitAreaList.Count * num1 > (float)this._hitIndex + 0.5f);
+     * 这段代码, 可以采用 Prefix, GetDeleteArrowDistance() 只在两个地方调用过, 另一处就在上面的 if 分支中 (即非 AutoPlay 情况)
+     */
+    [HarmonyPrefix]
+    [HarmonyPatch(typeof(SlideRoot), "GetDeleteArrowDistance")]
+    private static void FixSlideAutoPlayArrow(
+        SlideRoot __instance, ref bool ____hitIn, int ____hitIndex, List<SlideManager.HitArea> ____hitAreaList,
+        float ___StarLaunchMsec, float ___StarArriveMsec, float ___lastWaitTime
+    )
+    {
+        if (GameManager.IsAutoPlay())
+        {
+            float prop = (NotesManager.GetCurrentMsec() - ___StarLaunchMsec) / (___StarArriveMsec - ___StarLaunchMsec - ___lastWaitTime);
+            ____hitIn = ____hitAreaList.Count * prop > ____hitIndex + 0.5f;
+        }
+    }
+    
+}
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