The invention relates to a combination duct aircraft. The combination duct aircraft consists of a combination duct central body and an even number of fan-shaped single duct flying bodies; a flight control system is arranged in the combination duct central body; the fan-shaped single duct flying bodies are detachably, symmetrically and uniformly arranged on the outer side of the combination duct central body to form an annular combination duct aircraft together. The combination duct aircraft is formed by assembling in a detachable manner; the number of the single duct flying bodies can be regulated according to a requirement so as to meet the requirements of different load and different purposes; meanwhile, the combination duct aircraft is simple in structure and convenient to load and unload; the single duct flying bodies and the combination duct central body form a circular main body structure, so that air resistance and noises can be reduced; the flight is safe and stable; the control is precise; the reactive torque balance is realized by adopting a reactive torque grid fin of a brand new structure, so that the balance is quick and accurate; the energy consumption required for the balance is reduced; the requirements of vertical take-off and landing and stable flight of the aircraft are met.