The invention discloses a method for activating an adiponitrile hydrogenation catalyst. The method is characterized in that the catalyst is a modified raney nickel catalyst and is activated by the method comprising the following steps: preparing a mixing solution from iron, chromium, molybdenum, bismuth, manganese or tungsten soluble salts and NaOH respectively; slowly adding the modified raney nickel catalyst and ammonium salt; heating with microwave and reacting, and then washing; the modified raney nickel catalyst is prepared by the method comprises the following steps: grinding nickel-aluminum alloy into powder; adding to a mixing solution to dissolve part of aluminum, wherein the mixing solution is prepared through NaOH, ammonium salt and ammonium hydroxide in certain ratio; washing with deionized water and absolute ethyl alcohol; adding the powder to the mixing solution consisting of ferric nitrate and a modifier under a microwave condition and reacting to obtain a solid; drying and roasting the solid; and then charging hydrogen and reducing to obtain the modified raney nickel catalyst. With the adoption of the method for activating the adiponitrile hydrogenation catalyst, the prepared catalyst is relatively large in specific surface area, loss of the modifier is small, and high conversion rate of adiponitrile and high selectivity of hexamethylenediamine are achieved in the adiponitrile catalytic hydrogenation process.