The invention discloses a method for preparing an iron oxide red hybridization pigment by means of clay minerals. According to the method, natural clay minerals are dispersed in water to form suspension liquid after being subjected to breaking, double rolling and ball milling, molysite and auxiliaries are then added, evenly dispersed and transferred into a hydrothermal reaction kettle, pH of the solution is controlled to be 0.5-4, reaction lasts for 5-60 h at the pressure of 2-8 MPa and the temperature of 160-300 DEG C, and programmed cooling is conducted at the rate of 10 DEG C/min to indoor temperature; the solid product is separated, washed, dried and smashed to generate the bright red hybridization pigment. Structural evolution and recombination are induced through hydrothermal reaction, reaction parameters are precisely controlled, exchange is conducted between Fe3+ and ions in clay minerals under the action of auxiliaries, in-situ formation of a crystalline phase is achieved, the novel silicon-aluminum iron oxide red hybridization pigment with bright color, high stability and uniform size is obtained, and the cost-effective red hybridization pigment is provided for multiple fields including coating, paint, ceramic and ink.