The precision of calibrating the CCD’s optics-electron characteristic will directly affect the measured result. A new calibrate method was introduced after the analysis of several methods of calibrating CCD’s optics-electron characteristic had been performed. The ration relationship between I/I0(the relative light intensity distribution of Airy pattern in theory) and n(the position of CCD’s pels) had been deduced. In the data processing

the conics fitting method was adopt to locate the peak value of grey scale curve and the alignment of the peak of theory light intensity curve and that of measured grey scale curve was completed. In practical experiment， a given CCD was calibrated using this method and the result was reliable.