Abstract: A vehicle with a hydrostatic transmission system of wheel motor type in which the wheel motor is specially designed to meet the strict requirements of the vehicle, with a maximum mechanical efficiency of 0.97, speed ranging from 0 to 1500 r.p.m. for both fixed displacement and continuously variable displacement, and a wide speed ratio. It is compact in size, simple in construction, and easy to produce. The system may include a manual or automatic control device of the continuously variable displacement motor or pump and a distributing valve which can control the individual working mode of each wheel motor, so that the adjustable speed range can be further extended and the mean efficiency of the vehicle can be improved.