diff --git a/src/OceanScene.js b/src/OceanScene.js
index d1eed95..c9462ea 100644
--- a/src/OceanScene.js
+++ b/src/OceanScene.js
@@ -291,6 +291,7 @@ export class OceanScene {
             maxHeight: 34, // 海面以上地形的最大起伏高度
             waterLevel: 0, // 海平面基准高度
             underwaterDepthBias: 4.5, // 整体压低海面以下地形，避免浅滩露出
+            underwaterBiasFadeWidth: 8, // 水下额外下沉的渐变宽度，越大近岸越平滑
             landBias: 0.2, // 整体抬升陆地倾向，增大陆地露出面积
             falloffStartRatio: 0.22, // 从中心向外开始下沉的起始比例
             maxLandRatio: 0.46, // 大陆海岸线的大致外缘比例
@@ -299,7 +300,8 @@ export class OceanScene {
             continentLift: 0.55, // 核心大陆的额外抬升强度
             coastVariance: 0.05, // 海岸线形状起伏幅度，越大越不规则
             outerShelfDepth: 4, // 大陆外侧陆架的额外下沉深度
-            seed: 42 // 固定随机种子，保证地形稳定复现
+            coastlineBlendWidth: 42, // 海岸线外侧过渡到海底的缓冲宽度
+            seed: 23 // 固定随机种子，保证地形稳定复现
         });
         
         this.terrain = terrainGen.generate();
@@ -317,8 +319,8 @@ export class OceanScene {
             terrainSize: 1200, // 随机植被允许分布的地形范围
             waterLevel: 1, // 植被生成时参考的水位，避免贴近海边
             treePlacements: [ // 手动指定树木坐标
-                { x: -180, z: -120, rotation: 0.4, scale: 1.6 },
-                { x: -120, z: -40, rotation: 1.2, scale: 1.35 },
+                { x: 0, z: 50, rotation: 0.4, scale: 1.6 },
+                { x: 21, z: 32, rotation: 1.2, scale: 1.35 },
                 // { x: -40, z: -150, rotation: 2.1, scale: 1.75 },
                 // { x: 70, z: -70, rotation: 2.8, scale: 1.45 },
                 // { x: 135, z: 15, rotation: 4.1, scale: 1.55 },
diff --git a/src/TerrainGenerator.js b/src/TerrainGenerator.js
index 9681952..b0df497 100644
--- a/src/TerrainGenerator.js
+++ b/src/TerrainGenerator.js
@@ -11,6 +11,7 @@ export class TerrainGenerator {
         this.shoreWidth = options.shoreWidth || 3.5;
         this.shoreDepth = options.shoreDepth || 1.5;
         this.underwaterDepthBias = options.underwaterDepthBias || 3.5;
+        this.underwaterBiasFadeWidth = options.underwaterBiasFadeWidth || 6;
         this.landBias = options.landBias ?? 0.18;
         this.falloffStartRatio = options.falloffStartRatio || 0.24;
         this.maxLandRatio = options.maxLandRatio || 0.48;
@@ -19,6 +20,7 @@ export class TerrainGenerator {
         this.continentLift = options.continentLift || 0.35;
         this.coastVariance = options.coastVariance || 0.08;
         this.outerShelfDepth = options.outerShelfDepth || 2.5;
+        this.coastlineBlendWidth = options.coastlineBlendWidth || 32;
         
         this.noise = new SimplexNoise(options.seed || 42);
         this.terrain = null;
@@ -96,7 +98,8 @@ export class TerrainGenerator {
         let edgeDepth = 0;
         if (distFromCenter > falloffStart) {
             const t = (distFromCenter - falloffStart) / Math.max(0.0001, coastlineRadius - falloffStart);
-            continentMask = Math.max(0, 1 - Math.pow(t, 1.2));
+            const easedT = THREE.MathUtils.smoothstep(t, 0, 1);
+            continentMask = Math.max(0, 1 - Math.pow(easedT, 1.05));
             edgeDepth = -this.edgeDepth * Math.pow(Math.max(0, t), 2);
         }
         
@@ -105,12 +108,13 @@ export class TerrainGenerator {
 
         if (distFromCenter > coastlineRadius) {
             const t = THREE.MathUtils.clamp(
-                (distFromCenter - coastlineRadius) / (this.size * 0.08),
+                (distFromCenter - coastlineRadius) / this.coastlineBlendWidth,
                 0,
                 1
             );
-            const forcedSeaFloor = this.waterLevel - this.outerShelfDepth * Math.pow(t, 1.1);
-            height = Math.min(height, forcedSeaFloor);
+            const forcedSeaFloor = this.waterLevel - this.outerShelfDepth * THREE.MathUtils.smoothstep(t, 0, 1);
+            const blend = THREE.MathUtils.smootherstep(t, 0, 1);
+            height = THREE.MathUtils.lerp(height, Math.min(height, forcedSeaFloor), blend);
         }
         
         const shoreMin = this.waterLevel - this.shoreWidth;
@@ -126,7 +130,13 @@ export class TerrainGenerator {
         }
 
         if (height < this.waterLevel) {
-            height -= this.underwaterDepthBias;
+            const underwaterDepth = THREE.MathUtils.clamp(this.waterLevel - height, 0, this.underwaterBiasFadeWidth);
+            const biasStrength = THREE.MathUtils.smootherstep(
+                underwaterDepth / this.underwaterBiasFadeWidth,
+                0,
+                1
+            );
+            height -= this.underwaterDepthBias * biasStrength;
         }
 
         if (Math.abs(height - this.waterLevel) < 0.06) {