Due to the single geometric error control parameters of multi axis CNC machine tools, the identification results are inefficient. Therefore, an efficient identification method for geometric error variation region of multi axis CNC machine tools is proposed. The geometric structure, motion principle and error term of multi axis CNC machine tool are analyzed. The ideal motion characteristic matrix is taken as the contrast term to establish the spatial positioning error model of multi axis CNC machine tool. The assembly error of different multi axis CNC machine tools is taken as the input value, and the geometric error control parameters are added. Under the spatial positioning error model of multi axis CNC machine tool, the geometric error detection and identification device is installed. In addition, the corresponding error is calculated with the error source as the center, and the identification results of geometric error variation area of multi axis CNC machine tool are obtained from translation and rotation angle. The experimental results show that the identification accuracy of the proposed method is higher, the consumption time is shorter, and the application efficiency is guaranteed.