Abstract: In analyzing the present condition of the spacecraft assembling management, this paper presents the design of the JIT system, where the instruction card and the material card are combined in the MRP mode, the B/S mode and the C/S mode are combined, using the standard J2EE construction and the Oracle 9i data platform. The Assembling Management Platform is constructed with four levels, and the system framework is composed of seven modules. With the system, the information of planning, technology, production, management in the assembling work can be jointly accessed, which greatly improves the efficiency.