The invention discloses a high-activity
amorphous silica-
alumina, a hydrocracking catalyst supported by
amorphous silica-
alumina, and preparation methods thereof. The preparation method of the
amorphous silica-
alumina supporter comprises the following steps: preparing a
silicon source-aluminum source mixed water solution, mixing the mixed water solution with a precipitant solution, carrying out cocurrent flow
coprecipitation to obtain a precipitated
slurry, transferring the
slurry into a closed vessel, aging, molding, and
roasting. The invention also provides a preparation method of a hydrocracking catalyst by using the amorphous silica-alumina as the supporter. The preparation method of the hydrocracking catalyst is as follows: in the preparation method of the amorphous silica-alumina supporter, a
nickel salt or
nickel salt and
metal aid M salt is / are added into the
silicon source-aluminum source mixed water solution in the step (1), and the rest steps are the same as those in the preparation method of the amorphous silica-alumina supporter. The
coprecipitation process is adopted in the preparation process, and the
silicon source and aluminum source finally exist in the catalyst in the form of the amorphous silica-alumina, but the catalyst has much higher activity than the common amorphous silica-alumina catalyst.