The invention discloses a waterproof protection box for a marine generator and belongs to the field of marine equipment, the protection box comprises an oil filling pipe and a spacing plate, a drying agent storage bin coats the oil filling pipe and is connected with a waterproof rack, the waterproof rack is connected with a bearing frame through a fixed connecting piece, a breather pipe is arranged on the side wall of the waterproof rack, the spacing plate is connected with a pulling column, and the spacing plate is connected with a cable. According to the invention, the beneficial effect comprises: the protection box can perform multiple waterproof work on the generator through a way of physically insulating water and adsorbing water, air induction can be performed on the protection box, the oil plant utilization efficiency of the generator can be improved, and the mounting process is simple.