The invention discloses a flight control system of an UAV. The system comprises a ground control terminal and the UAV. The UAV is provided with a flight control device and a task execution device. Theground control terminal is used for receiving a task input by a user, and sending the task to the task execution device; the task execution device is used for adjusting the pointing direction and thepointing angle of a corresponding component according to the task, and sending the adjusted angle data to the flight control device; and the flight control device is further used for judging a flightintention according to the angle data and controlling flight of the UAV according to the flight intention. Through data interaction between the flight control device and the task execution device, one person can control flight and task execution at the same time, and task execution efficiency and flight safety are improved.