Form is the information carrier in the application system. The process of form system, workflow system and the coupling pattern of the workflow engine and form in the traditional workflow form system were analyzed. The definition of the form model and workflow model was deeply studied based on the modeling method, and they were combined in the process of modeling. The mechanism of dividing the workflow form by fields and sharing the same form in the same workflow model was exploited at the same time, and also a developing method of workflow form system based on shared model was presented. This method adopts form engine and workflow engine technology to separate form data and process of workflow data and make workflow engine deal with form data according to the combination of form model and process model. The detailed introduction of the process and characteristics of the method was also given.