The invention relates to a building indoor keel installation construction method. A device comprises a positioning device, an installation device and a connecting device, the installation device is installed at the upper end of the positioning device, the connecting device is installed at the upper end of the installation device, the positioning device comprises a cylindrical box, universal wheels, mercury, a rotating column, a hollow ball, a circular plate, a rotating frame and a telescopic bracket, and the installation device comprises an arc-shaped long plate, a supporting plate, rollers and a fixed plate. According to the building indoor keel installation construction method, a keel is always in a state parallel to a horizontal plane without being limited by an installation site through the positioning device, so that the influence of the installation site on keel installation in the installation process is prevented, the installation difficulty is reduced, the keel is installed and positioned through the installation device, the keel is connected with a suspension rod through the connecting device, and the keel is fixedly installed with the suspension rod under the action of gravity.