Ceiling type joist installation structure

The invention discloses a ceiling type joist installation structure. The structure comprises an M8 screw rod, an expansion screw tube, a first M8 nut, a main joist, a second M8 nut, a subsidiary joist and a connecting piece, one end of the expansion screw tube is connected to a wall, the other end of the expansion screw tube is connected with the M8 screw rod, the M8 screw rod is connected with the main joist in the X-axis direction, the first M8 nut and the second M8 nut are arranged above and below the main joist respectively and on the M8 screw rod, the subsidiary joist in the Y-axis direction is connected below the main joist, and the subsidiary joist is connected with the main joist through the connecting piece. According to the ceiling type joist installation structure, the M8 screw rod passes through an elliptical hole in the main joist, so that the connection process is simple and easy to operate; a main joist body passes through the inner side of the connecting piece, and an upper bent piece of the connecting piece is pressed and bent downward and buckled in a V-shaped groove in the main joist, so that the subsidiary joist can be adjusted in the X-axis direction according to the site construction conditions; by simplifying the connection structure between the main joist and the roof, the distance between the suspended ceiling and the roof is decreased, and the space which can be used by a user is increased.