The utility model discloses a moisture -proof terminal box, including box and fan, it opens or the apron of sealed box to be equipped with one on the box, a fixed mounting rubber layer in the break joint crack of apron and box, the conduit of the perpendicular fixed mounting of box lower extreme more than one, conduit one end all sets up in the external world, the other end all sets up inside thebox, the inside inner tube that all is equipped with of conduit, port about the inner tube is all to the flanging, and all with the internal face fixed connection of conduit, all form the sealed cavity of a drum structure between inner tube and the conduit, the inside drier of all filling of cavity. The utility model discloses simple structure, convenient to use, the effectual moisture of avoidingof ability are inside the getting into the of the gap of incoming line, and the ability is effectual with the inside moisture discharge of box, has increased the aridity and the security of inside.