Abstract: A complex reducing recoil technology was put forward, which combines a high-efficient muzzle brake and a time-delay nozzle flow anti-recoil device with a new damping adjustable high energy absorbing buffer, to effectively reduce the recoil of the small caliber automatic gun firing continuously. A complex rigid-flexible-coupling mathematical model for simulating recoil of the automatic gun was set up. Through the simulation analysis, the calculation result curve was basically consistent with the experimental curve. The test data show that the complex reducing recoil technology can effectively make automatic gun recoil significantly reduced. Therefore, the complex reducing recoil technology will provide a theoretical basis and application reference for future research on the low recoil firing of a small caliber automatic gun.