Steering differential performance is an important factor affecting the driving performance of the vehicle. A hydraulic control method is proposed for the differential system of the hydraulic wheel-driving off-road vehicle, and the driving force equalisation technique is adopted to realise the adaptive steering differential under the different speed modes. Based on the analysis of the working principle of static pressure driving steering differential, the mathematical model of the steering differential system is derived by using kinematics and dynamics theory. The hydraulic driving system and multibody dynamics model are established by AMESim and LMS Virtual.Lab Motion, respectively, and joint simulation is carried out. The experimental scheme is designed for the typical working conditions in the simulation, and the rotation speed and the pressure differential of the motor in the steady state are analysed. The experimental results are consistent with the theoretical analysis and simulation results, which indicate that the system can achieve a better steering differential performance. This research provides a new idea for the study of the steering performance of the hydraulic wheel-driving walking system, which is of great practical significance to improve the driving performance of off-road vehicles under the complex terrain.