The variable speed pneumatic monorail crane gearbox was taken as the research object, the three-dimensional model of the gearbox body was built in Pro/e software, and the three-dimensional model of the gearbox body is imported into ANSYS Workbench finite element software in the form of seamless connection. According to the actual stress condition of the gearbox body under the working state, the static model of the gearbox body was established. Based on the ANSYS Workbench static analysis module, the whole deformation nephogram and the equivalent stress nephogram of the gearbox body, the deformation and the maximum stress of the gearbox body under the working state were obtained.The 1-6 order vibration nephogram and natural vibration frequency of the box was got, the basis of the reliability of the box was analyzed, and the gearbox design met the safety requirements.