The invention discloses a software module dividing method, and aims to realize module division in a software system structure. The software module dividing method comprises the following steps: carrying out dispersion coding on software module division by using the characteristic of swarm optimizing of a particle swarm optimization; meanwhile, evaluating a software module division result by using a high-cohesion and low-coupling software design principle; using a position updating mode based on a software modularized evaluating standard, wherein position updating every time is close to optimal software module division; and finally obtaining a software module division result. The software module dividing method is high in rate of convergence, good in stability and good in dividing effect, and is used for optimizing the structure of a software structure.