The invention relates to a fireproof door used on a building. The fireproof door comprises a door frame and door plates which are respectively arranged at two sides of the door frame. The fireproof door is characterized in that the door plates are respectively glued with the door frame through bonding layers and nailed with the door frame through connecting members, and at least one side of the door plates is a counter-fire side and is a fireproof plate. The invention has the outstanding substantive characteristics that 1, at least one door plate is the fireproof plate, so that a flame retardant purpose is achieved; 2, the door frame, door mullions and an unexposed side are made of flame retardant materials and cannot spontaneously ignite at a relatively higher temperature, and the fireproof effect of the fireproof door is further improved; 3, a heat insulating layer is filled in a cavity formed by the two door plates, the door frame and the door mullions, which is favorable to reducing the high temperature of the counter-fire side, transferring the heat of the counter-fire side to the unexposed side, preventing the temperature from gradually raising and promoting flame retardant wood to lie in an environment below the spontaneous ignition temperature as much as possible; and 4, a metal layer is also arranged on the outer side of the counter-fire side, and deformation phenomena which are caused as different parts of the door plates lose different contents of water are avoided.