The detonation process is very close to the constant volume combustion process, engines based on a constant volume combustion process have higher thermodynamic efficiency than traditional constant pressure combustion cycle engines, the potential advantage of thermal cycle efficiency has become the main reason for studying knock engines. Nozzle studies have shown that the use of convergent-divergent nozzles in pulse detonation engines can significantly improve propulsion performance. For a given filling time, the thrust of a single-tube pulse detonation engine is considered by the ignition pressure, ignition interval, valve closing and purge time. In order to compare the advantages and disadvantages of single-tube pulse detonation engine and multi-tube pulse detonation engine, the multi-tube simulation performance with different ignition frequency and thrust performance is discussed. Compared with the single-tube results, it was found that the multi-tube improves the stability and pulse value of engine performance. This study uses the HMSTH AUSMD method to solve the detonation wave problem, and analyzes the difference between the shock wave at the nozzle of the single-tube and multi-tube detonation engines and the shock wave at the nozzle outlet.