Abstract: A building information modeling (BIM)-based modular housing built with thin-wall channel steel can include columns and transverse beams adopt inward-flanging C-section steel or combined square steel arranged by oppositely buckling symmetric inward-flanging C-section steel. The columns and transverse beams are connected to each other together by base connectors, butting connectors, or crossed connectors. The joint is provided with webs, and can be used as a standard connector due to high strength, thereby realizing an internal-external nesting effect. A positioning groove arranged outside the joint and the inward-flanging C-section steel can be nested together in a concavo-convex manner, and then pressed and fastened by a fastening steel strip, thereby realizing effects of fastening and slippage prevention.