The invention provides a gas compressor with a stability enhancing and effect improving device. The gas compressor comprises a casing, a wheel hub and the stability enhancing and effect improving device. A high-pressure gas suction hole, a gas ejecting hole and M gas jetting holes are formed in the casing. High-pressure gas is sucked into the stability enhancing and effect improving device through the high-pressure gas suction hole. Gas at the top of an intermediate-stage movable blade and gas at the root of an intermediate-stage static blade are sucked into the stability enhancing and effect improving device through the gas ejecting hole. The mixed gas is ejected to the top of a low-pressure-stage movable blade through the gas ejecting hole. By means of the gas compressor with the stability enhancing and effect improving device, the gas at the root of the intermediate-stage static blade and the gas at the top of the intermediate-stage movable blade can be sucked out, the thickness of a boundary layer of the area at the root of the intermediate-stage static blade and the vortex strength of an angle area can be reduced, flow separation of the areas is inhibited, the functions of reducing flowing losses and improving the efficiency of the gas compressor can be achieved, flowing blockage and gas backflow of the areas during instable work of the gas compressor are relieved, and the function of enlarging the stable work range of the gas compressor can be achieved.