The invention discloses a hydrocracking method comprising the steps that raw oil is divided into raw oil I and raw oil II according to a certain proportion; the raw oil I is mixed with hydrogen and is heated by a heating furnace I, and then, the mixture enters a hydrorefining reactor together with an effluent from a hydrocracking reactor and reacts under the action of a hydrorefining catalyst; the raw oil II is mixed with a tail oil distillate and is heated by a heating furnace II after being mixed with a hydrogen-rich gas, and then, the mixture enters the hydrocracking reactor and reacts under the action of a hydrocracking catalyst, wherein the reaction effluent of the hydrorefining reactor is separated and distillated to obtain the hydrogen-rich gas, a light naphtha distillate, a heavy naphtha distillate, middle distillate oil and a tail oil distillate. The method provided by the invention can be used for treating heavy distillate oil and producing the middle distillate oil at the maximum quantity.