The invention relates to the technical field of agricultural and animal husbandry intelligent equipment, and particularly relates to an unmanned aerial vehicle pesticide spraying control system, a pesticide spraying device and an unmanned aerial vehicle. The system comprises an information acquisition device, an information processing device and a water pump driver. The information acquisition device is used for acquiring flight speed information of the unmanned aerial vehicle and current flow velocity information of the pesticide spraying device in real time and transmitting the information to the information processing device. The information processing device is used for calculating pesticide spraying preliminary flow velocity according to the flight speed information of the unmanned aerial vehicle based on the preset rules and generating a water pump flow control correction signal according to the pesticide spraying preliminary flow velocity and the current flow velocity information and also used for controlling the correction signal to correct an original water pump flow control signal according to the water pump flow so as to generate a water pump flow control signal. The water pump driver is used for adjusting the flow velocity of the pesticide spraying device according to the water pump flow control signal. Therefore, the pesticide spraying process can be accurately controlled without cooperation of an unmanned aerial vehicle controller and agricultural personnel so as to realize intelligent pesticide spraying control.