The invention relates to a one-step synthesis preparation method of a hydrocracking catalyst. The method comprises the following steps of under the condition of stirring at 20 to 50 DEG C, adding an acidic aluminum salt solution into a mixed solution of a Y molecular sieve, sodium silicate, an accessory ingredient and deionized water, controlling a final pH (Potential Of Hydrogen) value of neutral reaction to range from 6 to 8, and carrying out stirring reaction for a period of time; under the condition of stirring at 60 to 80 DEG C, adding the acidic aluminum salt solution and a concentrated sodium metaaluminate solution at the same time, controlling a pH value of a reaction system to range from 6 to 8; under the condition of stirring at 80 to 90 DEG C, adjusting a pH value to range from 8 to 9, and aging; cooling sizing obtained after the aging, then adding a nickel salt and tungsten salt solution, uniformly stirring, carrying out solid-liquid separation and ion exchange, washing and purifying to obtain filter cake dry glue, and finally, performing drying, extrusion moulding and roasting to obtain the hydrocracking catalyst. The hydrocracking catalyst prepared by adopting the method provided by the invention has good active component dispersion, high catalyst activity and long service life; the preparation method can be used for preparing the high-efficient catalyst through one-step synthesis, and is low in cost and suitable for industrial production.