對象池是一個單例類：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ObjectPool  {
    private static ObjectPool instance;
    private ObjectPool()
    {
        pool = new Dictionary<string, List<GameObject>>();
        prefabs = new Dictionary<string
 
, GameObject>();
    }
    public static ObjectPool GetInstance()
    {
        if (instance==null)
        {
            instance = new ObjectPool();
        }
        return instance;
    }

    /// <summary>
    /// 對象池
    /// </summary>
    private Dictionary<string,List<GameObject>> pool;

    
 
/// <summary>
    /// 預設體
    /// </summary>
    private Dictionary<string, GameObject> prefabs;

    /// <summary>
    /// 從對象池中獲取對象
    /// </summary>
    /// <param name="objName"></param>
    /// <returns></returns>
    public GameObject GetObj(string objName)
    {
        
 
//結果對象
        GameObject result=null;
        //判斷是否有該名字的對象池
        if (pool.ContainsKey(objName))
        {
                //對象池裏有對象
            if (pool[objName].Count>0)
            {
                //獲取結果
                result = pool[objName][0];
                //激活對象
                result.SetActive(true);
                //從池中移除該對象
                pool[objName].Remove(result);
                //返回結果
                return result;
            }          
        }
        //如果沒有該名字的對象池或者該名字對象池沒有對象

        GameObject prefab = null;      
        //如果已經加載過該預設體
        if (prefabs.ContainsKey(objName))
        {
            prefab = prefabs[objName];
        }
        else     //如果沒有加載過該預設體
        {
            //加載預設體
            prefab = Resources.Load<GameObject>("Prefabs/"+objName);
            //更新字典
            prefabs.Add(objName, prefab);
        }
      
        //生成
        result = UnityEngine.Object.Instantiate(prefab);
        //改名（去除 Clone）
        result.name = objName;
        //返回
        return result;
    }

    /// <summary>
    /// 回收對象到對象池
    /// </summary>
    /// <param name="objName"></param>
    public void RecycleObj(GameObject obj)
    {
        //設置為非激活
        obj.SetActive(false);
        //判斷是否有該對象的對象池
        if (pool.ContainsKey(obj.name))
        {       
            //放置到該對象池
            pool[obj.name].Add(obj);
        }
        else
        {
            //創建該類型的池子，並將對象放入
            pool.Add(obj.name, new List<GameObject>() { obj });
        }

    }

}

以後要生成對象就獲取單例通過GetObj()來獲取，對象回收就調用RecycleObj(),這樣就減少了生成和銷毀預制體的性能消耗

Unity對象池的實現