The invention discloses a catalyst for producing low-freezing point diesel oil, and a preparation method thereof. The preparation method of the catalyst comprises the following steps: 1, preparing an aqueous organic alkali solution with the concentration of 0.15-0.80 mol/L, adding USY molecular sieve to the solution, carrying out treatment at 50-90 DEG C for 0.5-3 h to prepare modified USY molecular sieve, adding fumed silica and modified beta zeolite powder, fully rolling above materials, molding the rolled materials, drying the molded materials, and roasting the dried materials to obtain a catalyst carrier; and 2, impregnating the catalyst carrier obtained in step 1 in an impregnating solution containing active metal components, drying the impregnated catalyst carrier, and roasting the dried impregnated catalyst carrier to obtain the hydrocracking catalyst. The catalyst prepared through the method, adopting the novel modified molecular sieve, has the characteristics of high hydrocracking activity and good isomerism, and the obtained hydrocracking diesel oil product has a low freezing point.