A study about the influence factors on effective thrust of pulse detonation engine ( PDE) is carried out to obtain effective thrust. The continuous detonation combustion of air-breathing/gasoline-air PDE is achieved by using the cyclone-type aero-valves in a detonation tube with diameter of 60 mm. The effects of the filling speed of detonation tube and the stamping flow speed on the drag of PDE are analyzed based on the cold-state experiments,while the pressure p3 of the aero-valve is studied in the thermal-state experiments. The results of calculation for the thrust and drag in a period show that PDE can output effective thrust at the frequency of 10 Hz,but this effective thrust is difficult to be measured under actual working conditions. The research on the continuous effective thrust for PDE indicates that the operating frequency,detonation intensity, internal and external drag are the decision factors,while reducing the spoiler drag is the key to obtain the effective thrust.