Based on the basic principle of four-quadrant-based tracking sensor, the centroid detection error and the displacement sensitivity of four-quadrant detector, caused by noise or crosstalk in multiple anode photomultiplier (PMT tube), are analyzed in detail. The tracking error formula of four-quadrant-based tracking senor is given in theory and verified in experiment. The results show that when the photon-electron number per frame is constant, the tracking error of four-quadrant-based tracking senor increases as the crosstalk in multiple-anode PMT increases, and when the crosstalk in multiple-anode PMT is constant, the tracking error of four-quadrant-based tracking senor decreases as the photon-electron numbers increases.