Based on a certain aero-engine simplified exhaust cavity radar cross section （RCS） test results， the contribution of the stabilizer taking the reduction measures to the engine’s rearward cavity RCS is analyzed. Based on the traditional structure of the afterburner， the simplified cavity RCS calculation models of five different stabilizer evaporation chambers are established for the existing structure. The RCS characteristics of different stabilizer evaporation chamber structures are compared at high frequency 10 GHz and low frequency 1.5 GHz. The results show that， in the traditional non-stealth integrated design of the exhaust cavity structure， the stabilizer can achieve an obvious reduction effect of RCS at high frequency after adopting stealth measures. Several kinds of modified design for the structure of evaporation chamber of the flame stabilizer can bring a certain reduction benefit at high frequency， and the reduction at low frequency is not obvious. The flat structure with transverse and longitudinal composite angle inclination（WDQ5） has better improvment on RCS reduction than other structure， and can improve the working condition of absorbing coating and its reliability.Stabilization of the stabilizer at 0°—20° has a certain inhibitory effect on the RCS of the backward cavity.