The invention relates to the technical field of agriculture, in particular to a pesticide spraying device and method, and particularly discloses an automatic and accurate pesticide feeding device and method for an agricultural UAV. The automatic and accurate pesticide feeding device for the agricultural UAV is characterized in that a first lifting unit is mounted on a trolley; a pesticide conveying box is arranged on the trolley, connected with the UAV and used for feeding pesticide to the UAV; a second lifting unit is connected with the first lifting unit, and a weighing unit is arranged on the second lifting unit; and a controller is used for controlling ascending and descending of the first lifting unit and the second lifting unit, receiving a signal of the weighing unit and controlling the pesticide conveying box to feed the pesticide to the UAV. According to the automatic and accurate pesticide feeding device, the accurate controlling of UAV dosage is achieved, the maximum take-off load is not exceeded when the pesticide is fed to the UAV, or fast and accurate feeding is realized according to a dosage requirement of accurate pesticide application, and the work efficiency of the UAV is improved; and further, the device can perform mobile operation, so that the problem that the carrying is inconvenient when the pesticide is fed to the UAV is solved.