Abstract: Firstly,the thermoacoustic oscillation coupling theoretical model between the duct acoustic propagation and instability heat release was presented in this paper.Secondly,this model was used to analyze and predict the longitudinal equivalence frequency and stability in an aero-engine afterburner.The average flow parameters of the afterburner were gained by computational fluid dynamics(CFD) simulation,providing conditions for the application of thermoacoustic oscillation theory of the afterburner.By analyzing the results of calculating cases for heat release position and perforated rate of heat shield,some reference criteria were provided for the engineering design of the aircraft afterburner instability and the control method was disclosed.