The invention discloses a composite ignition type combustion light gas gun. The composite ignition type combustion light gas gun comprises a drive section, a driven section, a convergence section, anemitting tube and an ignition control system, wherein one end of the drive section is sealed, and the other end of the drive section is connected to the driven section, and a joint is clamped with a diaphragm; the tube body of the driven section is equipped with a pressure sensor; the front end of the convergence section is connected to the driven section, the rear end of the convergence section is connected to the emitting tube, and the joint of the rear end and the emitting tube is clamped with a diaphragm, and an igniter is mounted on a tube body; a shot is placed on a position, close to the diaphragm, in the emitting tube; and the ignition control system comprises a pressure sensor, a charge amplifier, a digital delay pulse generator. The light gas gun utilizes a composite ignition form, adopts mutual action between detonation waves induced by convergence shock wave reflection and detonation waves forcibly detonated by the igniter to generate intense shock waves, then, the intenseshock waves chase after the shot and are reflected, so that shot-bottom pressure is instantaneously increased, and a gas gun system with higher operation efficiency is developed with a lower price.