Abstract: In order to optimize loader transmission ratio, the transmission ratio was redesigned based on using condition. When the loader worked in gearⅡ and III, the left and right axle shaft of the front and rear bridge torque curves, and the steering pump, variable speed pump and the work pump pressure curves were tested and recorded. The probability torque average values were calculated by the probability distribution, then the input and output characteristics were obtained when the engine and the torque converter working together, and the minimum fuel consumption point of the output torque and the corresponding output torque value were found. Maintaining gear I and IV transmission ratio unchanged, in accordance with the principle of the gear II and III probability torque average value was matched with the torque of the lowest fuel consumption point in the working together output characteristics, the loader gear II and III transmission ratio were redesigned, and the values were 2.433 and 1.264 respectively. By simulating, the fuel consumption of the loader working under the new transmission ratio in the loop condition was 13.85L/·h, which decreased 1.33 L/h than the original. The new design can improve the fuel economy.