Abstract: Simulator is becoming more and more important for the research of P2P，though it has not attracted much attention.This paper first analyses the working mode of BT software，makes deep research on the open source General P2P Simulator（GPS），and discovers that the BT protocol has some defects，which will affect the validity of simulation.Their flow evaluation algorithm will consume so much memory that the simulation efficiency will be affected.Moreover，the simulation nodes that are created at the beginning can not quit after the download has finished，which will affect the dynamic of the simulation.Based on the previous research，some improvement is made to provide an effective and steady general simulator for the study of Bittorrent system and its network behavior.

Key words: BT software, General P2P Simulator（GPS）, simulator analysis, simulator improvement

摘要： 模拟器逐渐成为研究P2P的主要工具，但其本身却没有受到多少关注。分析BT软件的工作方式，对开源通用P2P模拟器（GPS）进行深入研究，发现其实现的BT协议算法存在缺陷，影响了模拟的真实性。其流量评估算法消耗大量内存，影响了模拟的效率。其模拟节点在开始时就要全部产生，下载后不能自动退出，影响了模拟的动态性。通过对这些不足的改进，提供一个真实稳定的通用模拟器并用于研究Bittorrent系统和它产生的网络行为。

关键词: BT软件, 通用P2P模拟器（GPS）, 模拟器分析, 模拟器改进