The invention discloses a preparation method of a polyaniline-coated carbon fiber hybrid gas-sensitive material with a cross-linked structure, belongs to the field of material synthesis and gas sensors, and aims at solving the problems that when existing conducting polymers serve as the gas-sensitive material of the gas sensors, the gas-sensitive response time is long, and the stability is poor. The preparation method comprises the following steps that 1, polypyrrole is prepared; 2, the polypyrrole is carbonized at constant temperature under protection of inert gas and then cooled to the room temperature to obtain carbon fibers with the cross-linked structure; 3, aniline monomers are mixed with an aqueous hydrochloric acid solution, the carbon fibers with the cross-linked structure are added, ultrasonic mixing is performed for 1 h, an ice-water bath is performed under protection of the inert gas, an aqueous hydrochloric acid solution of ammonium persulfate is slowly dropwise added, reacting is performed for 24-48 h after dropwise adding is finished, washing is performed with water for two times and then performed with absolute ethyl alcohol and acetone, drying is performed, and then the polyaniline-coated carbon fiber hybrid material is obtained. The preparation method is mainly used for preparing the polyaniline-coated carbon fiber hybrid gas-sensitive material with the cross-linked structure.