In order to realize photometric measurement, two types of measurement way are established. First, the system composition and the contrast measurement principle are introduced, and then wide spectrum measurement way and filter measurement way based on the analysis of engineering are proposed. If G-type stars and space target in the same field of view, the wide spectrum measurement way can be chosen; if G-type reference stars is less, filter measurement way can be chosen; measuring error analysis for these two ways is given. Finally experimental results indicate that the wide spectrum measurement way has high signal noise ratio(SNR); the limiting magnitude is 16 mv
, and the measurement precision can reach 0.15 magnitude under better weather condition; under the same SNR condition, due to the less energy detected by filter measurement way, limit magnitude is 14 mv
; under the condition of small weather changes, measurement precision can reach 0.02 magnitude. Two types of measurement errors are almost the same, but the number of stars calibrated by the wide spectrum measurement way increases by 2.4 times, which is advantageous for the data processing and calculation.