A combined bolt relates to a central control bolt for a burglar-proof door, and includes a decorative sheet, a lock box and a bolt, wherein the lock box consists of a housing and an inner plate, the decorative sheet is connected with the inner plate of the lock box, and the bolt is arranged in the lock box; the bolt includes a rack, a gear, a rotating shaft and a rotating shaft support; the rotating shaft support is arranged between the inner plate and the housing of the lock box, the rotating shaft is mounted on the rotating shaft support, and one end of the rotating shaft penetrates the inner plate to be connected with the gear and fixed on the housing of the lock box; and the gear is connected with the rack. Compared with the existing central control bolt for the burglar-proof door, in the creation, the decorative sheet, the bolt and the lock box are integrated; as long as a hole is formed in the door, the bolt can be used, and the bolt is convenient to mount and improves the integral appearance of the door; and as a door crack adjusting block is arranged in the lock box, the combined bolt integrates the functions of a door lock, the bolt and the door crack adjusting into a whole.