The invention belongs to the pneumatic system energy saving field, and realizes an air and magnet combined multi-cavity and multi-blade motor. When in usage, in order to reduce the consumption of high pressure air, the principle of homopolar repulsion of a permanent magnet repel is employed, each blade end of a rotator which is obliquely arranged suffers the repulsive force from the permanent magnet of a stator, and the power rotating in counter-clockwise direction is generated; meanwhile, between the dead point spot of each blade and the two stator magnetic poles, a valve mechanism is used to generate a gust of strong wind, thus the blades can rotate and pass through quickly; when the blades of the rotator are not between the stator magnetic poles, compressed air stops blowing, so that the consumption of the compressed air can be reduced and the rotating power is obtained continuously. Compared with a traditional pneumatic motor, the motor disclosed by the invention can remarkably reduce consumption of compressed air and provide continuous rotating power with very small amount of compressed air through occasionally blowing.