The invention relates to an efficient drain water recovery box which comprises a cylindrical box body, spraying pipes, vapor condensation fins and an exhaust port. The cylindrical box body is a vertical thin-wall cylinder. The multiple spraying pipes are arranged in a criss-cross manner and are horizontally arranged in the cylindrical box body, and spraying holes which are evenly distributed are formed in the spraying pipes. The vapor condensation fins are arranged in the cylindrical box body and located below the spraying pipes and comprise the multiple condensation fins which are arranged in parallel. The condensation fins are hollow platy pipes which are horizontally arranged and are filled with condensate. The exhaust port is formed in the upper portion of the cylindrical box body, and a filtering net cover arranged in the cylindrical box body is further arranged at the lower end of the exhaust port. The efficient drain water recovery box has the beneficial effects that a large quantity of vapor is condensed into water immediately after making contact with the vapor condensation fins, the rest of vapor directly encounters foggy drain water sprayed down through the spraying pipes which are arranged in the criss-cross manner, the vapor is basically completely absorbed in the foggy drain water and does not move upwards any more, only an extremely-small quantity of vapor overflows and is almost negligible.