The invention particularly relates to an unmanned aerial vehicle with an efficient heat diffusion effect, comprising a fuselage, a power propeller fixed at the top of the fuselage and an undercarriage fixed at the bottom of the fuselage, wherein an engine compartment and a circuit board are arranged in the fuselage. The unmanned aerial vehicle also comprises a ventilating device fixed above the fuselage, wherein the ventilating device comprises a contraction section in a hollow circular truncated cone structure, a diffusion section in a hollow circular truncated cone structure and a circular tube throat connected with the top surface of the contraction section and the top surface of the diffusion section; a negative pressure tube is fixed on the circular tube throat; the negative pressure tube is communicated with the circular tube throat; and the negative pressure tube is connected with the engine compartment through a connecting tube. According to the unmanned aerial vehicle provided by the invention, by additionally arranging the ventilating device communicated with the engine compartment and the heat diffusion equipment arranged on the lower surface of an electric hot plate, during flight, an engine and the circuit board have good heat diffusion effects; and the engine does not need to additionally supply power, so that the load of the engine can not be increased.