The dynamics model of electric vehicle with motorized-wheel-drive based on AMESim was built, and the differential drive assist steering (DDAS) control system model was built using Matlab/Simulink. On this basis, the control strategy of torque distribution between right and left front steerable wheels was presented, aiming for the reduction of the steering efforts and assisting the steering wheel return to center, as well as the yaw compensation produced by differential drive of the rear two wheels. The co-simulation results validated that the proposed DDAS control system could improve steering handiness, steering feel and returnability of the steering wheel, including stability compensation and practicability enhancement for DDAS system. Furthermore, the double-lane change road experiments for rapid control prototyping of DDAS control strategy were conducted. Experimental results verified the feasibility of providing steering assistance and the ability to keep road feeling of DDAS system.