In order to reduce the operating energy consumption of high-power locomotive traction motor, an energy-saving control method for locomotive traction motors based on dynamic distribution of traction power is proposed. Firstly, based on field operation data, a mathematical model between traction motor efficiency and its traction effort and running speed is established. Then, using the interval velocity and traction operating curve planned by the automatic driving system, the traction motor energy consumption under different traction distribution strategies is calculated based on the mathematical model. The traction power distribution scheme with the minimum objective function value is selected to control the traction output of each axle of the locomotive. Finally, the proposed method is simulated and analyzed based on the operating data of a certain line and each section of the HXD1 automatic driving locomotive, and the effectiveness of the method is verified.