Abstract: In order to improve the machining performance of the machine tool, it is crucial to study the accuracy of the machine tool, so a kinematic model of a 3PRS parallel pendulum angular head for high-efficiency milling and machining of large and complex curved surface parts is established, and then error analysis is carried out. The mechanism, with 3 degrees of freedom, is validated by the modified K-G formula. The position-inverse solution of the mechanism is further analyzed. On this basis, structural parameter errors are considered, and a program embedded in Ansys is utilized to calculate the tool point pose. By comparing the pose errors of two groups, preparation for subsequent kinematic calibration and error compensation experiments is facilitated.