The present invention discloses an anti-condensation ring main unit comprising a cabinet and a base. One side of the cabinet is provided with a cabinet door hinged through a hinge, the top of the cabinet door is provided with a cover body, the other side of the cabinet door is provided with an opening part which allows the internal air of the cabinet and the outside air to circulate with each other. A barrier part is provided in a region, outside the cabinet, of the opening part, and is used for partitioning or urging the internal air of the cabinet and the outside air to circulate with each other. A first temperature detector and a second temperature detector are arranged inside and outside the cabinet respectively, and the outputs of the first temperature detector and the second temperature detector are sent to a controller for judging whether the internal temperature of the cabinet is higher or lower than the external temperature of the cabinet. The controller is connected with a driving device which controls the barrier part to make the corresponding movement when the internal temperature of the cabinet is higher or lower than the external temperature of the cabinet so that the inside of the cabinet and the outside of the cabinet are enabled to have air circulation, or no air circulation.