Abstract: Most of loader gear transmission ratio was distributed by geometric series or paranoid geometric series based on experience. These transmission ratio distribution methods have some limitations. Loader use of gear was experienced, then various gear efficiency was counted. According to the input characteristics of engine and torque converter working together and loader output characteristics curve, the traction characteristics curves are made. The objective function was established considering gear efficiency, and optimazition of loader transmission ratio was made by complex method. Loader performance simulation software was built, to calculate the fuel economy of loader before and after optimization. Optimization results show that the higher utilization of low-bit, the smaller interval of transmission ratio between low gear. Optimazition results reflect the actual use conditions on the distribution of the transmission ratio, can improve the fuel economy of loader.