The invention discloses a method for testing the gas detonation wave absorption effect of a cavity structure. The method comprises integrating a pipeline, a flange, bolts and nuts, a cavity, a pressure sensor, a flame sensor, an electrode, an AC power supply, an vacuum pump, a digital vacuum gauge, a high-purity methane cylinder, an air compressor, a circulation pump, an air pressure valve, an airsuction valve, an intake valve, a first circulation valve, a second circulation valve, accelerators, a diaphragm, a steel sheet, a dynamic data collector, a high-speed camera, and a host computer into a test system to perform a test, wherein the material of the cavity is high-strength transparent synthetic glass; one end of the cavity is a taper angle structure with an included angle of 120 to 160 degrees, 3 to 6 accelerometers are disposed in a premixed acceleration section, and the high-speed camera is at least 105 frames per second. The method can study the attenuation laws of the shock wave propagation velocity, the flame propagation velocity and the impact strength of the gas detonation before and after passing through the cavity structure, and explore the gas detonation wave absorption effect of the cavity structure.