Load-pull test of motor wheel truck is importaut for pull performance exaimnatiou and service quality security. The pull test system described in this paper cau simuatle any operating duty of the whole truck in a static position and collect relevaut test data.Based on these data, one can easily identify situation greatly reduce overhaul time and improve test quality. This paper is to present the founction, composition, principle of measure and control, relevant software and application of the system for readers in order that users can fully understand the system.