Satellite photoelectric imaging system can detect and recognize target at long distance. Maximum detection distance is its main property parameter. Based on the sun retro-reflection light of space target, several factors including sun light incidence angle, effective aperture of optics system, detector′s signal-to-noise ratio (SNR) threshold and exposure time are analyzed to provide the mathematical model of the maximum detection distance. The results show that the limitation detection distance improves notly when the optics system effective aperture increases; the decrease in SNR threshold can improve the detection capability markedly and sun light incidence angle change has little influence when SNR threshold and sun light incidence angle vary simultaneously.