The invention discloses a preparation method for a cobalt-doped zinc oxide gas-sensitive material and application thereof, which relate to the technical fields of material chemistry and gas-sensitivesensors. Polyvinylpyrrolidone (PVP), zinc acetate and cobalt nitrate hexahydrate are dissolved in 75ml of ethylene glycol, wherein polyvinylpyrrolidone, the molecular weight of which is 400,000, is 0.3g, the molar ratio of cobalt nitrate hexahydrate to zinc acetate is between 0.025 and 0.233, and thereby the cobalt-doped nanoscale spherical zinc oxide gas-sensitive material is prepared. Because amicrowave-and-ultrasonic wave-co-assisted solvothermal method is adopted in the process of preparation, the cobalt-doped nanoscale spherical zinc oxide material has high detection sensitivity and goodselectivity; and the preparation method is simple and harmless to the environment, and effectively overcomes defects existing in the prior art, for example, preparation methods are complex and cost is higher and production process conditions are strict, and sensors have high working temperature, low response and recovery speed and short service lives.