This ejection system for unmanned aerial vehicles utilizes self-independent technology which include the air supply system with no pipelines, central air passages in different locations, direct injection with bilateral controls, measurement and control with digital circuits, digital parameter setting, networked information transmission and digital safety blocking system. It features stable and safe operations, strong power, easy maintenance as well as low using costs. The pneumatic restoration design keeps the loss of compressed air at a low level, bringing the intervals of every two ejections down to less than 5 minutes. The system is highly integrated and is able to operate with no extra power supply, wires and equipment. It means that this system is operable under all conditions with simply one man operation. Gas-powered catapult steers clear of most of the defects experienced by its regular counterparts like infrared exposure of wake flames during rocket assisted ejection as well as the formidable costs and complex peripherals of electromagnetic launch. The system uses cheap compressed air, generating no sound, light and wake flame and thus is highly safe, technological and economic. The six-meter release slip accelerates a drone up to 150kg to a release speed of 30m/s with each release costing only several cents. With high mobility and practicality, this ejection system can be towed or mounted onto a vehicle and doesn't require much of operation sites and environments.