Most of workflow management systems in the market are based on centralized defining in the organization. Further more, they have poor ability to describe the complex process, and have difficulty to deal with the business process share between cross-organizations. To support virtual and cross-organizational workflows in distributed environment, WfMSs must realize cross-organizational and distributed management to improve the dependability and extensible etc. To solve these issues, a Web-based lightweight process modeling system has been developed in this paper. This system is based on Java and XML technology, and provides friendly GUI which is easy to be used. The model document can be saved in XML format, so the interoperation between different workflow products becomes easy. This system establishes the base for enacting the WfMSs.