Abstract: A fast frequency domain method for predicting sonic boom propagation was proposed based on classical Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation.Furthermore,the sonic boom properties along the normal direction to the shock front were obtained by augmenting the Mach angle into the equation.To demonstrate the feasibility of the method,the results were compared with the experimental data of the model C presented in NASA TD N-161.The flow field of the supersonic moving vehicle was first calculated by a computational fluid dynamics(CFD) method with different grids.Then,the sonic boom propagation was computed based on the proposed KZK model with the input of the Fourier analysis results from CFD.The prediction results are in good agreement with NASA experimental data.It is also shown that the sonic boom decays rapidly in the near field due to the nonlinearity effects.In the far field,the sonic boom becomes axisymmetric gradually due to the effect of sound diffraction.After long distance propagation,the sound energy is concentrated on low frequency component.