diff --git a/assets/script/game/common/config/GameSet.ts b/assets/script/game/common/config/GameSet.ts
index 390601fa..aac5191f 100644
--- a/assets/script/game/common/config/GameSet.ts
+++ b/assets/script/game/common/config/GameSet.ts
@@ -48,6 +48,8 @@ export enum FightSet {
     CSKILL_START_Y = 30,
     /** 护盾数值上限（数值减免型：1 点护盾吸收 1 点伤害） */
     SHIELD_MAX = 5,
+    /** 防御减伤平衡常数：减伤率 = defense / (defense + DEFENSE_K)，K 越大每点防御收益越低 */
+    DEFENSE_K = 500,
     WAVE_HEAL_RATE = 0.4, // 回合结束时所有英雄恢复最大生命值的比例（与 DDA 放水兜底分层：回血保节奏，放水防崩盘）
     PUNCTURE_DOWN = 50,
     /** 穿透伤害衰减系数：单体技能命中第2个及以后目标时按此比例折算伤害 */
diff --git a/assets/script/game/common/config/HeroAttrs.ts b/assets/script/game/common/config/HeroAttrs.ts
index 9f388756..d2372612 100644
--- a/assets/script/game/common/config/HeroAttrs.ts
+++ b/assets/script/game/common/config/HeroAttrs.ts
@@ -14,6 +14,7 @@ export enum Attrs {
     speed = "speed",            // 基础移动速度
     dis = "dis",                // 基础距离
     shield = "shield",          // 当前护盾
+    defense = "defense",        // 防御（除法递减模型：减伤率 = defense / (defense + DEFENSE_K)）
 
     // // ==================== 攻击属性 ====================
     // a_cd = "a_cd",              // 攻击计时
diff --git a/assets/script/game/hero/HeroAtkSystem.ts b/assets/script/game/hero/HeroAtkSystem.ts
index 8a884d10..8feeb91a 100644
--- a/assets/script/game/hero/HeroAtkSystem.ts
+++ b/assets/script/game/hero/HeroAtkSystem.ts
@@ -171,6 +171,10 @@ export class HeroAtkSystem extends ecs.ComblockSystem implements ecs.ISystemUpda
         }
         if (damage <= 0) return reDate;
 
+        // 防御减伤（除法递减模型，护盾吸收之后、扣血之前结算）
+        damage = TAttrsComp.applyDefense(damage);
+        mLogger.log(this.debugMode, 'HeroAtkSystem', "  after defense", damage)
+
         // TAttrsComp.hp -= damage; // 应用伤害到数据层
         TAttrsComp.add_hp(-damage); // 使用 add_hp 以触发 dirty_hp 和 UI 更新
 
diff --git a/assets/script/game/hero/HeroAttrsComp.ts b/assets/script/game/hero/HeroAttrsComp.ts
index 702f8487..e7c73034 100644
--- a/assets/script/game/hero/HeroAttrsComp.ts
+++ b/assets/script/game/hero/HeroAttrsComp.ts
@@ -39,6 +39,7 @@ export class HeroAttrsComp extends ecs.Comp {
     speed: number = 100;   // 基础移动速度
     dis: number = 100;     // 基础距离
     shield: number = 0;         // 当前护盾
+    defense: number = 0;        // 防御（除法递减模型减伤，见 getFinalDefense）
 
     // ==================== 攻击属性 (补充) ====================
     skills: Record<number, HSkillInfo> = {};
@@ -517,6 +518,26 @@ export class HeroAttrsComp extends ecs.Comp {
         return this.vulnerable_res + mods.flatSum + mods.pctSum;
     }
 
+    /** 最终防御值 = 基础 + 限时修饰（加法模型），供除法递减减伤公式使用 */
+    public getFinalDefense(): number {
+        const mods = this.aggregateTimedMods(Attrs.defense);
+        return Math.max(0, this.defense + mods.flatSum + mods.pctSum);
+    }
+
+    /**
+     * 按除法递减模型计算防御减伤后的伤害
+     * 减伤率 = defense / (defense + DEFENSE_K)，防御收益递减且永不达到 100%
+     * @param damage 护盾结算后的原始伤害
+     * @returns 减伤后的伤害，保底 1 点防止完全免伤
+     */
+    public applyDefense(damage: number): number {
+        if (damage <= 0) return damage;
+        const defense = this.getFinalDefense();
+        if (defense <= 0) return damage;
+        const reduced = damage * (FightSet.DEFENSE_K / (defense + FightSet.DEFENSE_K));
+        return Math.max(1, Math.floor(reduced));
+    }
+
     /** 根据攻速加成换算实际攻击间隔，避免直接改写配置里的基础 CD。 */
     public getEffectiveSkillCd(skillId: number): number {
         const skill = this.skills[skillId];
@@ -578,6 +599,7 @@ export class HeroAttrsComp extends ecs.Comp {
         this.speed = 100;
         this.dis = 100;
         this.shield = 0;
+        this.defense = 0;
 
         // 重置新增属性
         this.skills = {};