The invention discloses an electrostatic spraying type unmanned helicopter pesticide applying system. The system comprises an unmanned helicopter having a landing gear, a supporting frame, a storage battery, a high voltage electrostatic generator, an electric diaphragm pump, a pesticide box and two sets of electrostatic spraying devices, wherein the supporting frame and the landing gear are fixed; the storage battery, the high voltage electrostatic generator, the electric diaphragm pump and the pesticide box are fixed on the supporting frame; the electrostatic spraying devices are symmetrically arranged on both sides of the unmanned helicopter; and a liquid outlet of the pesticide box is communicated with a liquid inlet of the electric diaphragm pump, and a liquid outlet of the electric diaphragm pump is communicated with the liquid inlets of the electrostatic spraying devices by a tee joint respectively. The system has the advantages that the size of the sprayed charged droplets is quite small, so the droplets are high in deposition effect and uniformly distributed, in particularly, the droplets can be attached to the back surfaces of leaves of plants, the effective utilization rate of pesticide is guaranteed and the drift loss of pesticide is lowered; and the spraying amount can be remotely controlled, so the spraying amount of the system can be changed along with the change of the flying speed.