UML (Unified Modeling Language) is one of the latest fruits in software engineering field. It terminated the fighting in the field of modeling language of object oriented technology. But how to use UML to solve the real world problem is still the hot topic on the field. From the view of the requirements for software development, the flexible software development process is presented to fit the changing world, and the framework of integrated UML software development environment is designed to support modeling, simulation and round-trip development. The environment should be composed of UML visual modeling system,UML simulation system,UML code generation system and UML reverse translation system.