This paper presents a collaborative product development architecture (cPDA) using multi-agents which provides a framework for the design and analysis tools to effectively communicate and collaborate. This paper addresses two key issues. One is concerned with product visualization and real-time collaboration over the Internet. It discusses the light-weight geometric representation of the product information for efficient transmission and sharing over the Internet. The other is concerned with the collaborative process management using multi-agents. The collaborative product development process is globally managed by the process manager, but locally managed by agent interactions, which combines the advantage of the hierarchical management of the process with the heterarchical one.