Software process model provides the relationship among all phases of software developing . lt is the generalization and important content of software engineering . lt provides the management of softwaic engineering with milestone schedule and also provides the process of software developing with principle and methods 软件开发模型给出了软件开发活动各阶段之间的关系，它是软件开发过程的概括，是软件工程的重要内容，它为软件工程管理提供里程碑的进度表，为软件开发过程提供原则和方法。
