Abstract: To analyze the detonation characteristics and propulsive performance of pulse detonation engine (PDE) with conical divergent nozzle under different filling conditions, the CE/SE method using triangular meshes, which are suitable to the conical tube, has been proposed and applied to calculate the internal and external flow field of gasdroplets two-phase pulse detonation engine. The results show that the strong gradient such as detonation shock and complicated wave interaction patterns in the straight tube and conical tube can both be perfectly described by using this CE/SE method. When the conical divergent nozzle is not filled with fuel, the PDE achieves a higher fuel specific impulse, with more complex flow field, much lower pressure peak and bigger Mach peak appearing in the nozzle than that in the detonation tube. In contrast, simpler flow field and smaller pressure peak difference have been gained in the divergent nozzle of PDE when the nozzle is full filled with fuel. However, larger total thrust and bigger impulse of PDE are produced under this condition.