In order to investigate three-dimensional shock wave focus of two-stage pulse detmation engine(PDE), three-dimensional shock wave focus initiation principle device was independently designed, and a complete set of experimental system was established.Experiments on non-reaction three-dimensional shock wave focus were conducted.It is found that resonant frequency increases with the increase of the incidence angle of resonator.As airflow exit area decreases, resonant frequency of resonator increases and the dynamic pressure amplitude of resonator bottom increases.As nozzle diverging angle increases, the highest alpha-frequency increases and the quantity of beta-frequency increases.When the nozzle diverging angle is 30°, the dynamic pressure amplitude of resonator bottom is maximal.As ‘L’ increases, resonant frequency decreases and the dynamic pressure amplitude of resonator bottom decreases.