Abstract: Considering the factors of the installation of parts on the reducer shaft, the material and the processing technology of the shaft, the initial structure of the shaft was designed by using the minimum shaft diameter estimation method and shaft shoulder features. Aiming at the judgment of the rationality of the structure, the shaft was checked by using the strength check method. The rapid design of the shaft was developed by using MATLAB GUI module. Six kinds of independent computing blocks were designed in the system. The correctness of the calculation results was verified by comparison with the example results. According to the output calculation result of txt and combining with the parameterized design function of UG, the parameterized three-dimensional model of the shaft wss established. The results indicate that the system has the advantages of simple operation, high calculation efficiency and high precision, and improves the design efficiency of the shaft, and also provides a important reference for the development of other design systems.