Field bus technology has been widely used in vehicle electronics. For that distributed control system based on field bus can reduce electric system wiring, improve reliability, enhance information sharing, reduce repair difficulty, the application of field bus in electric drive vehicles will be the trend in future, and the time performance of field bus system will draw much attention. In order to share information of the field bus in a greater extent and to obtain a high level of decentralized control system, it is necessary to establish time coordinates between the subsystems, and then analyze the time performance of the field bus. This article introduces a design method of the distributed control system based on CAN bus for validating time characteristics precisely based on the distributed system of CAN bus. The experiment results verified its feasibility.