The ShanghaiGrid is an ongoing Grid Computing Environment (GCE) based on the Grid Service standards and the Open Grid Services Architecture. The ShanghaiGrid is a City Grid, which is to provide a general shared information Grid platform. Based on this point, a workflow management system is very import especially for user-defined workflow. By using the workflow, users in GCE would compose several Grid services as a new Service and provide it to others. This will enlarge the extensibility and business-originated usage in the GCE. This paper discusses the type of workflow, proposes a model of client-side workflow management system, and the design of several important workflow services. A service discovery process based on workflow is given in this paper too.