This paper investigates into vehicle traction performance enhancement using active differentials in the rear axle of a vehi- cle. Vehicle power-train system model augmented with active or open differential respectively is developed, which takes into account the drafts and wheel dynamics. The traction performances of vehicle are illustrated with computer simulations using Simscape/Driveline tool- box. Simulation results show that active differential is an effective device to obtain an asymmetric torque distribution by torque vectoring between right and left wheels with less energy loss, and it also possesses better acceleration performance in contrast with the open differ- ential on split-μ and slope road conditions.