To meet the requirements of the project management in collaborative design environment, the collaborative design task execution mechanism of task decomposition and allocation based on product structure tree is studied, and the task progress monitoring mechanism which is implemented by recursive weight statistical method is proposed to carry out the task progress control in the collaborative design execution processes. The product collaborative design process is taken as an example to analyze the method of process modeling by jBPM in detail. A project management prototype system based on B/S mode is structured based on MVC design mode by Java technology to verify the correctness of theoretical research and the feasibility of technology.