The invention belongs to a vehicle transmission, and provides a vehicle hybrid power system achieving multi-power-source coupling. The problems that as for an existing hybrid power system, a motor isexcessively large in torque and excessively low in rotating sped, and thus the system is large in size, large in weight and high in cost are solved. The vehicle hybrid power system comprises an engine, a first motor, a second motor, a speed reducer and an output flange disc; the speed reducer comprises a speed reducer box, an input shaft and an output shaft, and further comprises a one-way clutch,a planetary gear train, a first motor gear pair and a second motor gear pair which are arranged in the speed reducer box; the planetary gear train comprises a sun gear, a planetary frame, a gear ringand planetary gears; one end of the input shaft is arranged on the speed reducer box and connected with engine output, and the other end of the input shaft is arranged on the gear ring; one end of the output shaft is fixedly connected with the gear ring, the other end of the output shaft is fixedly connected with the output flange disc, and outer teeth of each planetary gear are engaged with inner teeth of the gear ring and outer teeth of the sun gear correspondingly; and a first motor passive gear is arranged on the outer side face of the gear ring, and a second motor passive gear is coaxially and fixedly connected with the sun gear.