Speed changer, power drive system and vehicle

The invention discloses a kind of speed changer, power drive system and vehicle.The speed changer includes：Multiple input shafts；Multiple output shafts, pass through shift gear auxiliary driving between output shaft and input shaft；First reverse idler gear and the second reverse idler gear, the second reverse idler gear engage with the gear driving gear on one in input shaft, and the first reverse idler gear is arranged to optionally link with the second reverse idler gear；Motor power axle, motor power axle overhead set is provided with motor power axle first gear and motor power axle second gear, the motor power axle synchronizer being additionally provided with motor power axle between motor power axle first gear and motor power axle second gear, motor power axle first gear engages with the first reverse idler gear, and motor power axle second gear is arranged to and a linkage in input shaft.The speed changer of the present invention can at least enrich the transmission mode of the power drive system with the speed changer to a certain extent.