The utility model relates to an indoor fire door in a building. The outside of the door frame is made of reinforced plastic plates, and the inside is filled with concrete. The door leaf is bonded together by a reinforced fiber grooved plate and a reinforced fiber flat plate. A steel frame is placed in the middle, and expanded perlite is filled in the middle. , The outer surface is composed of reinforced plastic sheets. Fire door size can be customized according to customer requirements, welcome to consult us.