In view of the RF stealth performance evaluation problems, this paper presents a method for fuzzy evaluating the RF stealth performance of the airborne radar system. Through analyzing the factors that radar radiation source influences the performance of the airborne radar system in the polarization domain, wave domain and energy domain, the RF stealth index of the waveform domain , polarization domain and the energy domain are constructed, a RF stealth evaluation method of the traditional "radiation reception" model is broken, the fuzzy evaluation method of radio frequency stealth based on the working state and working parameters of airborne radar system is established. Finally, the simulation evaluation of different airborne radar system is carried out. The results show that the method can correctly reflect the RF stealth performance of airborne radar system.