The invention belongs to the technical field of light gas gun experiments, and particularly relates to a light gas gun driven through hydrogen and oxygen mixed gas detonation, in particular to a two-stage light gas gun driven through hydrogen energy. According to the technical scheme, the two-stage light gas gun driven through hydrogen energy comprises a combustor, a gas injection device, an ignition device, a pump pipe, a high-pressure cone section, a transmitting pipe, a target chamber and a magnetic speed testing device, wherein the ignition device is installed at one end of the combustor, the other end, opposite to the end with the ignition device, of the combustor is connected with the pump pipe, and a pump pipe membrane and a pump pipe membrane breaker are arranged at the junction; the gas injection device is used for injecting hydrogen, oxygen and inert gas into the combustor; a piston is arranged in the pump pipe; the large-diameter portion of the high-pressure cone section is connected with the pump pipe; the small-diameter portion of the high-pressure cone section is connected with the transmitting pipe, and a transmitting pipe membrane and a transmitting pipe membrane breaker are arranged at the junction; shots are arranged in the transmitting pipe, and one end of the transmitting pipe is located in the target chamber; and the magnetic speed testing device is installed at the tail end of the transmitting pipe and connected with an oscilloscope. The two-stage light gas gun is driven through hydrogen energy instead of gunpowder, damage to the gun is small, no particular product is generated, and a gun barrel can be cleaned conveniently after experiments.