In order to make full use of the advantages of every electric vehicle (EV) driveway and reduce the demand of motor properties, a changing modes propulsion system was designed. According to the requirement of EV running conditions to power performance, this system can achieve modes transfusion between single motor driving, two motors joint driving and independent wheel driving. The working mechanism of this system and its influence to EV dynamic performance were analyzed. Because of realizing single motor driving, this system can effectively avoid the defects of EV abnormal running when one of the motors unexpected failure. Besides this, it has two speed transmissions and can effectively enhance the power performance of EV. So it is more flexible and reliable than independent wheel driving or focus driving, and can effectively improve the reliability and continued mileage of EV.