To improve the reliability of the highly-sensitive photoelectric detection system in the background of strong radiation, the calculation method of photoelectric imaging detection performance in the background of strong radiation is studied.The sensitivity model and SNR model of photoelectric detection are built based on the optical radiation characteristics of the target, and the calculation function of the charge crosstalk threshold is given.On this basis, the probabilistic models of photoelectric detection and imaging crosstalk are derived.A computational verification and an analysis are carried out.The results show that using an effective method of signal processing and spectral filtering can enhance the detection performance of the system.The target detection probability is increased from 0.3 to 0.95 and the crosstalk probability can be reduced to less than 0.05 by setting reasonable optical system parameters.