Aiming at solving the problem that the UAV can’t spray wettable powder and suspending agent, a kind of UAV which can spray solidliquid mixture was designed. Based on a certain type of eight rotor UAV, the machine is composed of a medicine tank with a stirring device, a nozzle which can spray solidliquid mixture medicine and landing gear of the UAV. According to the type of spraying agent, a liquid medicine tank with a stirring device is designed, and then the spraying of solidliquid mixture is designed and the hydrodynamics simulation is carried out. The UAV bracket to fix the liquid medicine tank is designed and the static and dynamic analysis is carried out. The battery is reconfigured according to the lift and endurance requirements of the UAV. The test results show that the concentration of the chemical liquid in the liquid tank is evenly distributed, and the concentration error is less than 10%; the spraying has good average coverage and average deposition parameters; the spraying operation with 5L of chemical liquid can last 15.5 minutes.