Prolonging the service time of CNC machine tools will lead to the deviation between the machining trajectory and the actual trajectory contour, and there are defects such as poor machining efficiency. In order to obtain the ideal machining effect of CNC machine tools, a control method of machining error of CNC machine tools based on laser tracker is proposed. Firstly, the laser tracker is used to determine the machining trajectory of CNC machine tools, and the cross-coupling controller is introduced to calculate the estimated trajectory error in the machining process of CNC machine tools. Then, the compensation control quantity of machining trajectory contour error is determined according to the error distribution result, and the machining control of CNC machine tools is carried out according to the interpolation value. Finally, the simulation test is carried out. The results show that this method reduces the machining error of CNC machine tools and improves the machining accuracy of CNC machine tools, which has high practical application value.