The invention provides a grain damp-proof storage box. The grain damp-proof storage box comprises a storage box body, wherein an air blower is mounted on one side of the storage box body, an air outlet pipeline is mounted at an air outlet of the air blower, a mounting seat is mounted on an inner top plate of the storage box body, a hollow column is mounted in the mounting seat, a fixing plate is fixedly welded to one side of the hollow column, an electric motor is installed at the top of the fixing plate, the output end of the electric motor is rotationally connected with a rotating shaft through a rotor, a straight gear is arranged at the end, away from the electric motor, of the rotating shaft in a penetrating mode, a bevel gear rack is connected to one side of the straight gear in a meshed mode, a rotating rod is installed on the side, away from the straight gear, of the bevel gear rack, and the end, away from the hollow column, of the rotating rod penetrates through the shell of the mounting seat and extends to the exterior of the shell to be connected with a rotating air spraying pipe. According to the grain damp-proof storage box, through the air blower and the rotary air spraying pipe, the ventilation range is enlarged, and the damp-proof effect of the storage box is improved.