Abstract: To estimate the influence of a single out-of-limit electrical equipment on the spacecraft electromagnetic compatibility at the system level, a simulation method is proposed for analyzing the spacecraft electromagnetic compatibility based on the EMC test results for the unit equipment, that is, to compare the simulated EMC test results for an equipment with the systematic susceptibility limits of the radiation, the transmission and the receiver sensitivity, with consideration of the installation position to obtain the safety margin. The simulation of a typical equipment (including non-RF products, RF products and power supply & distribution products) of an upright attitude two-compartment spacecraft model is carried out, and the influence of the exceeding EMC test results on the electromagnetic compatibility of the whole spacecraft and the rocket is analyzed. Comparison with the real test results shows that the above method can be used for effectively predicting the spacecraft’s electromagnetic compatibility at system level.