A joint hinge embedded keel takes an inverted triangle shape. The lower end of the keel is provided with a slot which is used for fixing an electric appliance panel and a roof decorative board. The keel is characterized in that a groove which is small outside and big inside is arranged at the middle of the upper end of the keel. In the joint hinge embedded keel, as the groove which is small outside and big inside is arranged at the middle of the upper end of the keel, the lower end of the joint hinge only needs to be made into an inserting block corresponding to the keel groove, the inserting block and the slot are inserted into the groove in parallel, and then the joint hinge is rotated 90 degrees, thus the connection of the joint hinge and the keel can be realized. In the site operation, the joint hinge can be added according to the sagging condition of the keel after mounting, thus the keel is characterized by convenient mounting.