中文摘要：

北京谱仪BESⅢ主漂移室（MDC）设计性能的提高要求更为精确的探测器模拟。文章主要介绍MDC的模拟，并对模拟中斜丝层几何构造和丝物质处理的方法进行了详细的描述。通过大量蒙特卡罗样本的产生和分析，表明模拟是合理的。

英文摘要：

The design performance of BESIII Main Drift Chamber（MDC） was improved, it required more accurate detector simulation. This paper introduced simulation of BESⅢ MDC , special emphasis is put on the geometry construction of stereo layer and wire materials. After mass data production and careful analysis, the simulation is proved workable and reasonable.