It is a challenging issue to exchange procedural CAD models between heterogeneous CAD systems. In this paper, we extend the synchronized collaborative design environment among heterogeneous CAD systems, which we developed previously, to a Web services based platform for exchange of procedural CAD models between heterogeneous CAD systems. First, the realtime exchange of one single operation is extended to the exchange of a complete procedural CAD model between heterogeneous CAD systems. Second, Web services technology is adopted to encapsulate the procedural CAD model exchange functions to a standard interface, which is then released on the Internet and can be easily used by remote developers in their windows applications, Web applications, and so on. Finally, a Web service for exchange of procedural CAD models between SolidWorks and Autodesk Mechanical Desktop is realized.