The invention discloses an installation tool for a civic building. The installation tool comprises an upper barrel and a lower barrel which are aranged coaxially and connected fixedly. The upper barrel comprises an inner barrel body and an outer barrel body which are arranged in a double-layer mode and connected through a sealing plate. The sealing plate is located in the lower position of the middle of the upper barrel. A first spring is arranged in an interlayer between the inner barrel body and the outer barrel body. The lower end of the first spring is connected to the sealing plate. The upper end of the first spring is connected with four guide sliding blocks. Guide sliding grooves formed in the axial direction are evenly distributed in the side wall of the inner barrel body. Through the installation tool, grub screws can be kept in a perpendicular state to be screwed into wood boards, an ideal fastening effect is achieved, and due to the arrangement of rotary barrels, operation can be conducted conveniently, efficiently and continuously.