The development process of a complex product should consider synthetically manufacturing and assembly process, and may be involved with many disciplines, such as mechanics, dynamics, vibration analysis, and so on. Conventionally, parameter design is carried out prior to tolerance design for economic considerations, and designers determined the parameter values separately, which may bring difficulties to other designers and lead to frequent redesign due to conflicts on some product specifications. This paper presents an approach based on constraint network to support concurrent and collaborative design. Firstly, from the point of view of concurrent engineering, the model of constraints network for current parameter and tolerance design, which consider the process of assembly and manufacture, is studied; Secondly, from the point of view of collaborative design, the model of constraints network for multidisciplinary collaborative design is studied. Finally, constraints network-based design method is studied, and optimization approach is presented, which synthetically consider parameter and tolerance, and enhance the design robustness. The method is demonstrated by a gear pump design problem.