Aiming at the problems of high cost and timeconsuming in volumetric error detection and identification of multiaxis machine tools, a novel identification method for linear axis positiondependent geometric error based on double ballbar test is proposed. Firstly, the error models of the axis motion in various planes are established, respectively; and the error element of each axis is prefitted with respect to its position using polynomial. Then, the comprehensive error in each plane is obtained with conventional threeplane circular arc trajectory measurement. Finally, the fitting coefficients are solved based on the least square method, which replaces the traditional method that directly solves the specific value of error element; and the positiondependent geometric error element identification of linear axes is realized. The experiment results verify the correctness and efficiency of the proposed method. The method has reference significance for the linear axis error identification and compensation of CNC machine tools.