The invention relates to an unmanned aerial vehicle low impact catapult pneumatic and hydraulic system which is composed of a main oil pump electromagnetic unloading overflow valve, a main oil pump, a main oil pump motor, a supplemented oil pump electromagnetic unloading overflow valve, a supplemented oil pump, a supplemented oil pump motor, a cartridge valve, a first one-way valve, a safety valve, a motor, an electric-hydraulic proportional cartridge valve, a second one-way valve, a safety and stop valve, a third one-way valve, an energy accumulator, a pressure reducing valve, a speed regulating valve, an electromagnetic change valve, a proportional overflow valve, a decelerating hydraulic cylinder, an oil tank and oil pipes communicated with each element. According to the unmanned aerial vehicle low impact catapult pneumatic and hydraulic system, the hydraulic motor is adopted so as to drive a winding drum mechanism, the shortages that a high-speed hydraulic cylinder is adopted by a traditional pneumatic and hydraulic system and thus technology is complex and machining difficulty is large are overcome; the hydraulic motor is controlled by a proportional valve and closed-loop control is conducted on the rotation speed of the hydraulic motor, so that the ejection with high reliability and low impact in a start stage is achieved, and the shortages that the traditional pneumatic and hydraulic system is large in impact and poor in reliability are overcome.