The invention relates to a waterproof bamboo/wood modification method. The waterproof bamboo/wood modification method comprises the following steps of (1) making preparations; (2) conducting vacuum impregnation on glycidyl methacrylate; (3) conducting vacuum impregnation on oxidized high-density polyethylene wax emulsion; and (4) conducting drying and surface treatment. Through pretreatment on bamboo/wood through the glycidyl methacrylate, the number of free hydroxyl groups in a base material is reduced, and oxidized high-density polyethylene wax is introduced and attached to cell walls of thebase material to achieve the waterproof purpose of reconstituted bamboo. The waterproof bamboo/wood modification method has the advantages that epoxy groups in the glycidyl methacrylate have an esterification reaction with the free hydroxyl groups in a bamboo material, the free hydroxyl groups are decreased, and meanwhile, the glycidyl methacrylate is grafted onto the cell walls of the bamboo material; ethyl alcohol is volatized under the high-temperature effect to provide a space for next-step immersion; the glycidyl methacrylate is copolymerized and combined with oxidized high-density polyethylene to prevent water from being immersed into a channel, and the number of hydrophilic groups is reduced.