In the process of fiveaxis machining of complex surface, the interpolation principle of CNC system will cause the rotation axis deviates from the ideal motion plane in the linear interpolation process, then nonlinear error is caused and the machining precision of surface is seriously affected.It is very important to study the influence of tool parameters on nonlinear error.The mathematical model of the influence of the tool parameters on the nonlinear error was obtained according to the motion law of the tool in the fiveaxis linkage process and the corresponding motion equation was established.The MATLAB simulation analysis on the nonlinear error caused by the three types of tools was done,the influence of the tool parameters on the nonlinear error was obtained and the measures to control the nonlinear error were put forward.Finally, the influence of the tool parameters on the nonlinear error was verified by the simulation of an impeller.