Trichogramma is adopted in biological agriculture because it is environmental friendly and has high efficiency in preventing pests. However, different from traditional liquid pesticides, trichogramma comes in small pill, which is difficult for manual dispensing, especially in Northeast China where corn is the main crop. Based on biological control and agricultural unmanned aerial vehicles (UAV) technology, this article proposed a trichogramma delivering system using Hex-Rotor UAV. The trichogramma autonomous delivery function was achieved through GPS and Google earth map. The Hex-Rotor’s basic structure and operating principle were explained, and a special trichogramma delivering device was designed. The entire system weighs 9kg at full load, and the UAV can fly for more than 20 min at the speed of 10m/s, complete serving an area of over 10hm2 on a single flight. A backstepping control algorithm with extended state observer (ESO) and fast differentiator was adopted, and the UAV can finish the trajectory tracking flight against external interference winds. Finally, the unit operation area of the delivery system reached 9700m2/min in practical tests. The trichogramma coverage was estimated almost 100% under ideal conditions, and work omission was 0. Experiments prove that this trichogramma delivering system possesses high stability and reliability, and can realize UAV autonomous biological control.