A method to produce an anti-swelling mica having following steps: mixing powdery mica with an alkaline compound to form a mixture; heating the mixture at a temperature between 150.degree. C..about.230.degree. C. for lasting 30 minutes to make metal ions out of the alkaline compound to diffuse into the mica homogeneously; using water to reduce temperature of the mixture so as to form an alkaline solution; separating the powdery mica from the alkaline solution to obtain a solid mica; neutralizing excessive alkaline compound adhering to the solid mica by an acid solution that is diluted by cold water and the mica anti-swells after adjusting pH of the solid mica to less than 7.0; and diluting the acid solution again by adding water and separating the solid mica from diluted acid solution to obtain a production--anti-swelling mica.