In order to analyze the geometric rotation accuracy of the rotor system, a set of rotor system tolerance model was established. Based on the small displacement spin volume, the key tolerances on the component assembly path are modeled, and the error transmission on the closed-loop link is analyzed by the homogeneous coordinate transformation method to obtain the geometric rotation accuracy model of the rotor system. On this basis, combined with Monte Carlo simulation, the example model of the rotor system is analyzed. The results show that the variation range of the root of the rotor blade in space is approximately an ellipsoid, which has complex fluctuations during the rotation. Among them, the radial fluctuation error percentage of the blade root in the plane of the blade is about 0.58%. The fluctuation in the direction perpendicular to the plane of the paddle is relatively large, about 0.89%.