由美国国家大气研究中心（NCAR）和宾夕法尼亚大学（PSU）共同开发的MM5模式是目前气象领域广泛采用的中尺度模式之一。由于MM5模式的广泛应用和计算特点，MM5 Benchmark成为了高性能计算领域衡量计算机实用性能的典型应用之一。本文介绍了MM5模式的并行计算方法，针对目前流行的Intel Itanium2 CPU特点，在性能分析的基础上，从编译选项、代码优化、区域分解、处理机拓扑结构等方面对程序性能进行优化。实际测试结果表明，在某国产巨型机上优化后的持续计算性能最大提高20％左右。

MM5 that is developed by NCAR and PSU is one of the most widely used mesoscale weather forecasting model,and the MM5 benchmark is becoming one of the representative applications to measure the performance of computers applied in the meteorology field because of its typical algorithm and popularity.This paper studies the parallel computing algorithm of MM5.According to the characteristics of the Intel Itanium2 CPU architecture,based on a computing performance analysis,the MM5 parallel computational efficiency is optimized from the aspect of compiler options,code tuning,partitioning methods and processor topologies.The optimization results indicate that  the MM5 implementation performance can be increased by 20% on a certain HPC platform based upon the Intel Itanium2 CPU.