The invention discloses an unmanned aerial vehicle used for releasing trichogramma for biological control, and belongs to the technical field of unmanned aerial vehicles. The unmanned aerial vehicle is a quad-rotor unmanned aerial vehicle, a GPS navigator, a GPS position indicator, a distance measuring sensor and an air pressure sensor are respectively mounted at the four corners of a center plateof the unmanned aerial vehicle, a releasing device assembly is fixedly connected under the unmanned aerial vehicle, an inner container and an outer container of the releasing device are nested, fixedly connected and sealed by a rubber ring, a baffle plate is arranged between the two containers and movably connected with the two containers, through holes are formed in the two containers and the baffle plate, and an arc-shaped groove is formed in the baffle plate, so that a hollow sphere, with holes, containing trichogrammas is conveniently released. A motor base is fixedly connected with the bottom of the outer container, an output shaft of a motor penetrates through a central hole II of the outer container and is fixedly connected with a central hole I of the baffle plate, and the pressure sensor is fixedly connected with a blind hole of the container II. The unmanned aerial vehicle used for releasing the trichogrammas for the biological control can be used for preventing and controlling rice stem borers in agricultural production, the rice yield can be remarkably improved, labor intensity of workers can be lightened, the size of the releasing device is reduced, the cost of the device is low, and the working efficiency is high.