Abstract A method of machine geometry calibration using 1-D ball array is presented. A series of balls are equal spaced fixed on a rigid bar. The spacings between balls are calibrated by a special laser interferometer. The position of the balls are sensed by a magnetic socket or a 3-D noncontact capacitive probe. The distinct feature of the ball array is that it gives 3-D positioning errors of the CMK simultaneously. It can be used for measuring all 21 source eroors and for error compensation of CMM. The straightness errors are measured by using reversal method. The angular error motions are determined by measuring the displacement or straightness errors of two parallel lines. The angular error are determined by using the diagonal lines. The 1-D ball array has low cost, high efficiency and high accuracy. It is expected to find wide applications in machine calibration and error compensation.