Workflow technology originated in the mid-seventies the twentieth century research in the field of office automation. After entering the nineties, with the personal computer, networking technology and promotion of the popularization, as well as the growing information technology to improve, making the research and development of workflow technology has entered a new boom. In this paper, based on the analysis of the reference model of workflow. We propose the workflow process definition model base on network-activities technology. definition of the workflow model has been improved the traditional mode in many side, This model use of atomic processes and sub-nodes of the concept of workflow templates, respectively in the node-level and sub-workflow to achieve the established level of reuse, so this paper have a certain reference value to workflow system.