Abstract: The frame structural system consists of a supporting system formed by columns and beams. Its assembly follows a "piece-by-piece to whole" lifting process. The installation accuracy of the steel frame structure’s columns and beams is closely related to both the stiffness of its own support structure system and the lifting scheme. This paper， in combination with an actual steel frame structure project， conducted lifting construction error monitoring and observed that the deviation direction was mainly in the axial connection direction of the columns and beams， indicating a cumulative error. Different benchmark support units and bolt tightening degrees were set as working conditions， and the stiffness of the structural system was calculated based on the finite element software ABAQUS. The results showed that the welding at the steel column base had little effect on the stiffness of the structural system， while the number of column-beam assemblies and the tightness of their bolted connections significantly influence the stiffness of the structural system. The benchmark support units promoted the transformation of the steel frame structure’s column-beam system from a frame structureal system with lateral displacement into one without lateral displacement， which fully exerted the benchmark control effect and benchmarking effect of the benchmark support units， eliminated error accumulation during the lifting of the steel frame structure’s columns and beams， and guaranted its lifting accuracy.