Turntable is a kind of equipment used for inertial component detection, which has high requirements for the structural performance of its shafting. The finite element method is used to analyze the main axle structure of ultra-low speed turntable in this paper. The analysis plays a guiding and verifying role in the design of turntable. Turntable bearings adopt air bearing. According to the actual situation, the spindle model is established to calculate the equivalent stiffness of air bearing. Then static analysis is carried out to solve the deformation and stress of the model in the static state. Finally, dynamic analysis is executed to obtain the vibration mode and natural frequencies of the structure, which verifies the rationality of the structure.