Abstract: The coupling relation of multidisciplinary collaborative design in CSCW is analyzed. First, constraints conditions and variable ranges are obtained from multidisciplinary specialists at the beginning of design phase. Then, multidisciplinary coupling parameters and correlative constraints are extracted. Finally, variational constraints network (VCN) model is established. The VCN model deals with inequality equation constraints, differential equations, synthesis of parameters & tolerances, and their integration with three dimensional CAD. The presented modeling approach establishes the foundation for parameter and tolerance collaborative design.