The invention provides a catalyst and a method for preparing epoxidized linseed oil through same, and belongs to the technical field of organic synthesizing. The catalyst is prepared through the following steps: a) roasting and grinding kaolin; and b) mixing grinded kaolin with calcium fluoride, cobaltous oxide and zinc oxide; heating the mixing system at the rate of 15-25 DEG C per minute until the temperature reaches 750-760 DEG C; and maintaining the temperature for 3-6h, thus obtaining the product. The composite catalyst is wide in raw material source, low in cost, simple in preparation processes, convenient to recover after being used, and extremely high in popularization value. The method comprises the following steps: 1) mixing linseed oil, a solvent and the catalyst; and 2) charging reaction gas; maintaining the system pressure in 1.1-1.2 atmospheric pressure; stirring to react for 2-4h under the temperature of 70-85 DEG C; and separating and purifying to obtain the epoxidizedlinseed oil. According to the method, the reaction processes are simple, direct, green and safe; and the epoxide number of the obtained product is beyond 10.