The utility model discloses a trussed girder of jacking platform and connection structure of smooth roof beam, smooth roof beam be through the smooth bottom of locating the trussed girder of sliding connection, sliding connection include with truss installation portion that the bottom of trussed girder is connected and locating the smooth roof beam installation department of truss installation troops under one's command side, the confession has been seted up on the smooth roof beam installation department smooth roof beam card is established and gliding smooth roof beam draw -in groove. The utility model discloses a bottom that the trussed girder of jacking platform was located to the roof beam cunning will be slided to sliding connection, replace traditional smooth roof beam and the mutual welded method of trussed girder, the effectual integrality of guaranteeing smooth roof beam, and the equipartition fine setting after the installation is accomplished to the smooth roof beam of being convenient for, recycles for the recovery of each component dismantlement of later stage and trussed girder and smooth roof beam simultaneously.