The invention discloses a fire hydrant hidden door which comprises a wood plaque, a wood base layer, a wood frame, a hidden door body, smoke preventing strips and hinges. The wood base layer is fixed to the surface of a wall, the wood frame is fixed to the side face of the wall and seamlessly combined with the wood base layer at wall corners, and the wood plaque is fixed to the wood base layer. The wood frame is connected to the hidden door body through the hinges, and the smoke preventing strips are arranged on the opposite rotating faces of the wood frame and the hidden door body. According to the fire hydrant hidden door, the wood base layer is fixed to the surface of the wall, the wood frame is fixed to the side face of the wall and combined with the wood base layer at the wall corners, and the hidden door body and the wall are combined more firmly; the smoke preventing strips can well protect internal firefighting equipment; and the hinges are hidden hinges, the wood frame is provided with notches, and the smoke preventing strips and the hinges are arranged on the side walls of the notches, so that more attractiveness is achieved while firmness is achieved.