Abstract: The tire lateral forcesisa key factor to affect vehicle lateral stability. However, it is difficult to be detected directly. The tire longitudinal force of a distributed drive electric vehicle can be calculated directly.It can be taken asinputquantities, and the totaltire lateral forces of the front and rear axle of the distributed drive electric vehicle areestimated based on the Unscented KalmanFilter (UKF) algorithm. The tire lateral forces distribution on the left and right side of axis are realized by combining the relationship between the vertical load and the tire lateral force. Through the co-simulation of CarSim and MATLAB/ Simulink, the estimation accuracies of the UKF and the direct calculation method were analyzed, and the superiority of the proposed method was verified. At the same time, the robustness of the estimation algorithm with parameter uncertaintieswere analyzed, and it is proved that the uncertainty of the quality parameter has a great influence on the estimation accuracy.