The invention discloses an automatic inflation floating body air shield dam gate anti-freezing method. According to the method, an automatic inflation floating body air shield dam gate anti-freezing device needs to be installed on the water surface and along a gate. The anti-freezing device comprises a pneumatic water surface turnover mechanism, a hydraulic water surface turnover mechanism, a floating body mechanism, an air pipe guide element and a control mechanism. The pneumatic water surface turnover mechanism is used for spraying air below the water surface within a first preset distance range from the water surface, and the hydraulic water surface turnover mechanism is used for spraying water below the water surface within a second preset distance range from the water surface. When the water surface temperature is lower than a first preset freezing temperature, gas is inputted to a hose or liquid is inputted to a water pipe. When the water surface temperature is lower than a second preset freezing temperature and the second preset freezing temperature is lower than the first preset freezing temperature, gas is inputted to the hose and simultaneously liquid is inputted to the water pipe. The method can well prevent the water surface from freezing and protect the gate.