The essence of the multidisciplinary collaborative design problem (MCDP) is the coordination of the design variables among multiple disciplines on the basis of the all constraints of all disciplines. There exist some problems such as the early detection of design conflicts and the determination of the consistency domains of the design variables, etc. The resolving of these problems can help designers avoid bad decision-making, reduce the design iteration and improve the design efficiency. Aiming at the problems, this paper proposes a constraint-net model to describe and manage all the design variables and constrains of all disciplines, discusses the reformulating method of the MCDP to improve computation efficiency, and develops the interval propagation algorithm to determine the consistency domains of the design variables, etc. A gear drive is taken as an example to illustrate the effectiveness of the proposed method.