The invention discloses a vertical takeoff and landing unmanned aerial vehicle with foldable fixed wings based on a dual-duct fan power system. A dual-duct fan power system which is horizontally arranged at the tail of the body of the unmanned aerial vehicle in a tail-driving arrangement is adopted, so that lifting force for vertical takeoff and landing and thrust for horizontal flying are provided for an aircraft; a control surface which is arranged at the exit of each duct in a deflected manner is used for providing vector thrust, so that quick attitude change is realized; wings adopt a folding wing configuration, when the aircraft vertically takes off and lands/ flies at a low speed, the wings are folded to decrease the frontal area of cross wind, and when the aircraft flies horizontally, the wings are unfolded to obtain large lifting force; and combined optimization of ducts and the wings is adopted, the wings are arranged in a specific duct air flow region, the duct suction generates a Coanda effect at a wing edge, so that the properties of the wings are improved. Multi-mold flight tasks such as vertical takeoff and landing, high-speed cruise, and the like of the aircraft are realized; the vertical takeoff and landing aircraft is high in aerodynamic efficiency during hanging in the air/flying at a low speed; and the vertical takeoff and landing unmanned aerial vehicle is high in anti-disturbance capacity during takeoff and landing/hanging in the air. The vertical takeoff and landing unmanned aerial vehicle is low in energy consumption, small in noise and high in safe reliability.