The gas film of a hybrid bearing with spherical spiral grooves was taken as the research object,based on a computationalfluiddynamics and six-degree-of-freedom coupled method,a dynamics model was developed to simulate the fluid flow in the gas film and the motion of gassupported rigid rotor.By analyzing the axis orbit and spectrum characteristics,the effect of machining and assembly errors,such as axis position and direction,structure dimension,and wall roughness,on the motion state of the rotor was studied.The results show that the assembly error has a great impact on the stability of the rotor,specifically when the revolving speed reaches 30 000 r/min,the position and direction errors of the axis reach 2 μm and 2°,respectively,the rotor amplitude is increased obviously and the bearing is in a limit cycle motion state,which is in a critical steadystate.Therefore,in order to ensure the movement stability of the hybrid bearing,the assembly precision of the axis should be ensured.When the bearing alignment is stable,the machining error has little effect on the bearing stability.