Combined height control method for unmanned aerial vehicle

The invention belongs to the technical field of unmanned aerial vehicle height control, and particularly relates to a combined height control method for an unmanned aerial vehicle, and the unmanned aerial vehicle comprises an unmanned aerial vehicle body, two wings and a height control mechanism. The height control mechanism comprises an air pump, an air cavity, a fixing plate, a sliding plate and an angle adjusting part; the angle adjusting part comprises a sliding rail, a sliding block, a connecting rod, a toothed plate, a gear and a rotating rod. The two wings are installed on the front side and the rear side of the aircraft body through bearings correspondingly. The air pump is fixedly installed in the machine body and connected with an external pipeline, the air cavity is fixedly installed below the air pump, the lower end of the air cavity is open and located below the machine body, the fixing plate is fixedly installed on the inner wall of the air cavity, a through hole is formed in the middle of the f