To implement the uniform load distribution of the power-split transmission, a pseudo static model is built. First, according to the method of theoretical analysis of tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA), the actual meshing process of each gear pair is simulated, and the fitting curves of time-varying mesh stiffness are obtained, which can improve the numerical precision. Next, according to the closed-loop characteristic of system power flow, the conditions for deformation compatibility of torsion angle are proposed, which are then combined with the torque equilibrium conditions and elastic support conditions to calculate the transmission torque of each gear pair. Finally, the load-sharing coefficient of the system is obtained, and the influence of the floating pinion based on spline clearance floating and constrained by the radial spacing ring is analyzed. The results show that the errors collectively influence the load sharing characteristics, only reducing a certain error never fully reach the perfect loading sharing characteristics. The floating component can significantly improve the load sharing characteristics. By comparing the theoretical data with the experimental data, the correctness of the method proposed is verified.