Process integration is the important aspect of product development process. The recent researches focus on project management, workflow management and process modeling. Based on the analysis of the process, product development process is divided into three levels according to different grains from macroscopy to microcosm. Our research concentrate on the workflow and the fine-grained design process. According to the need of representing the data and the relationships among them for process integration, context model is introduced, and its characters are analyzed. The tree-like structure of inheritance among context model’s classes is illustrated; The relationships of reference among them are also explained. Then, extensible markup language (XML) file is used to depict these classes. A four-tier framework of process integration has been established, in which model-view-controller patt is designed to realize the separation between context model and its various views. The integration of applications is applied by the encapsulation of enterprise’s business logic as distributed services. The prototype system for the design of air filter is applied in an institute.