A method of preparing a hydrocracking catalyst comprising a molded composite support of a zeolite molecular sieve with alumina, at least one of VIII Group metal components, at least one of VIB Group metal components and an organic additive, said organic additive being ethylene diamine tetraacetic acid, the method comprising mixing a zeolite molecular sieve and alumina and/or a precursor thereof, then molding and calcining the resulting mixture to prepare a molded composite support, and then simultaneously introducing into said molded composite support at least one of VIII group metal components, at least one of VIB group metal components and said organic additive, then drying the obtained catalyst at a drying temperature of 100-300°C for a drying time of 2-12 h, wherein said zeolite molecular sieve is one or more zeolite molecular sieves selected from the group consisting of a zeolite molecular sieve having faujasite structure, a zeolite molecular sieve having Beta zeolite structure and a zeolite molecular sieve having mordenite structure, wherein said zeolite molecular sieve has a B-acid/L-acid ratio higher than 0.9, and, when characterized by infrared spectrogram of hydroxy group, said zeolite molecular sieve has at least one characteristic peak of silicon-hydroxy group appearing in the range of 3760-3685 cm -1, wherein the B-acid/L-acid ratio is a ratio AB/AL determined from the IR spectrum of a sample by - grinding a zeolite molecular sieve sample and pressing it into a self-supporting tablet of about 10 mg/cm 2, - heat treating the tablet at 350°C under 10 -3 Pa vacuum for 2 h and then cooling to room temperature, - exposing the tablet to pyridine-saturated vapor for 15 minutes, vacuum pumping at 200°C for 30 minutes, and then cooling to room temperature, and - measuring the IR spectrum in a scanned range of 1,400-1,700 cm -1; wherein AB [(cm 2 g) -1] is the ratio of the IR absorption value in the range of 1,540 ± 5 cm -1 per unit area and unit mass of the sample, and AL [(cm 2 g) -1] is the ratio of the IR absorption value in the range of 1,450 ± 5 cm -1 per unit area and unit mass of the sample, and wherein the amounts of said various components are selected such as the content of each component in the obtained catalyst meets the following conditions: the content of the zeolite molecular sieve is 5 to 60 wt%, the content of said alumina is 15 to 80 wt%, the content of said organic additive is 0.5 to 30 wt%, based on the weight of the catalyst; and the content of said VIII Group metal Component is 2 to 8 wt%, and the content of said VIB Group metal component is 10 to 35 wt% calculated as oxide and based on the weight of the catalyst. mixing a zeolite molecular sieve and alumina and/or a precursor thereof, then molding and calcining the resulting mixture to prepare a molded composite support, and then simultaneously introducing into said molded composite support at least one of VIII group metal components, at least one of VIB group metal components and said organic additive, then drying the obtained catalyst at a drying temperature of 100-300°C for a drying time of 2-12 h, wherein said zeolite molecular sieve is one or more zeolite molecular sieves selected from the group consisting of a zeolite molecular sieve having faujasite structure, a zeolite molecular sieve having Beta zeolite structure and a zeolite molecular sieve having mordenite structure, wherein said zeolite molecular sieve has a B-acid/L-acid ratio higher than 0.9, and, when characterized by infrared spectrogram of hydroxy group, said zeolite molecular sieve has at least one characteristic peak of silicon-hydroxy group appearing in the range of 3760-3685 cm -1, - grinding a zeolite molecular sieve sample and pressing it into a self-supporting tablet of about 10 mg/cm 2, - heat treating the tablet at 350°C under 10 -3 Pa vacuum for 2 h and then cooling to room temperature, - exposing the tablet to pyridine-saturated vapor for 15 minutes, vacuum pumping at 200°C for 30 minutes, and then cooling to room temperature, and - measuring the IR spectrum in a scanned range of 1,400-1,700 cm -1; the content of the zeolite molecular sieve is 5 to 60 wt%, the content of said alumina is 15 to 80 wt%, the content of said organic additive is 0.5 to 30 wt%, based on the weight of the catalyst; and the content of said VIII Group metal Component is 2 to 8 wt%, and the content of said VIB Group metal component is 10 to 35 wt% calculated as oxide and based on the weight of the catalyst.