Abstract: According to the problems of calculation complexity and abstractness in the traditional analysis methods of serial-parallel mechanism, cutting machine for complex-surface was researched and the complete kinematic product of exponentials formula of serial-parallel mechanism was established based on the screw representation of spatial rigid motion. The errors of 4 D-H parameters were equivalent to error screw, and the practical screw coordinate containing error screw of every joint axis was established. With the practical kinematic product of exponentials formula of serial-parallel mechanism derived, the pose error model of tool coordinate system was established. According to the above screw method, the numerical calculation of cutting machine about kinematic and error was performed with MATLAB and the calculation results were compared with the simulation results of ADAMS. The comparison results show that the relative error of the two groups of calculation results is within the 0. 001 orders of magnitude, which certifies the correctness of screw method' s application in the analysis of serial-parallel mechanism.