Abstract: In this paper, a 1T2R 3-DOF cable-bar hybrid mechanism model is established in Unigraphics NX. On the basis of solving inverse kinematics equation. According to the differential theory of parallel robot, the mathematical model of the position and pose error of the moving platform of the cable-bar hybrid mechanism was established. The influence of the structure parameters and input parameters of the cable-bar hybrid mechanism on the position and posture error of the moving platform is analyzed by using MATLAB software. The results show that the length of three cables has the most sensitive effect on the output pose error of the terminal moving platform. Precise control is needed in the design and manufacture of test prototypes.