A new workflow technology, which is developed for product design process management (PDPM), is studied in this paper. Firstly, a new product tree structure, which associates workflow with components and solves process-data management problem, is put forward. Secondly, an improved flow structure consisting of workflow and dataflow and being driven by design-parameters is developed. Lastly, Dataflow structure for parameter integration is designed. A PDPM prototype system is developed and applied in engineering.