Abstract: Aiming at the problem that the domestic accelerator irradiation experiment could not fully meet the verification requirements of single particle anti-irradiation design for spacecraft，an Equivalent Fitting Algorithm for Evaluation of Single Event Effect (EFA-ESEE) was proposed in this paper. Based on the characteristics of anti-irradiation architecture, the reliability contribution coupling factor was constructed to obtain the equivalent coupling relationship between the cross sections of single event function interruption and linear energy transfer (LET) values of heavy ions. Hence, EFA-ESEE could reduce the dependence on irradiation experimental conditions and provide more reference data for spacecraft anti-irradiation design verification. Finally, through the comparison of radiation experiments, the algorithm model could be approximated to the evaluation and fitting of radiation experiment data so as to improve the reliability evaluation efficiency of spacecraft electronic equipment level system.