The MBMS(model base management system) is the kernel of a DSS(decision support system). The authors introduce the design and implementation of a client/server model base management system that runs on a heterogeneous distributed environment in this paper. In this system, a model is viewed as a program module and defined by a model IDL(interface definition language). By being organized with object oriented method and supporting remote and dynamic function (model) invocation transparently, the DSS may be developed easily and have very good static and dynamic extensibility. Also since many semantic information have been stored in the model base, the authors may develop more tools based on it to support the DSS development process.