Physical model and propagation mechanism of continuous detonation engine(CDE) were introduced.The wave structure of CDE was physically analysed.Two dimensional simplified model of CDE was simulated by two step chemical reaction model.The simulation results show a serial of detonation waves repetition processes along a 4 cm perimeter circle surface which is extracted from the cylindrical combustion chamber.The simulation results of the wave structures agree well with the corresponding experimental results.The numerical simulation results allow us get more detailed parameters of CDE and are good for further study of the CDE.