The non-uniformity effect of the four-quadrant detector on the output signal linearity and accuracy of trace were analyzed and position locating when the detector was used in the target trace,and the bottom limit to the non-uniformity was also given. Based on this,a multi-correction method,which used comprehensive compensation intensity distribution,dead current,and channel of amplifier coefficient was presented for the first time. By using this method,the non-linear error was limited to 5% and the accuracy of trace and position locating was 2%. Compared with the methods using the hardware correctioń of compensation channel of amplifier coefficient and the soft correction with dead current retained,the nonlinear error was reduced to 2% and the accuracy of position locating was improved nearly 3% by the multicorrection method.