The invention discloses an I-shaped reinforced-type steel structure for a building. The I-shaped reinforced-type steel structure comprises a steel structure upper supporting plate, a steel structure lower supporting plate, a first connecting plate and a second connecting plate. The steel structure upper supporting plate is horizontally arranged, the steel structure lower supporting plate is horizontally arranged below the steel structure upper supporting plate, and the first connecting plate and the second connecting plate are vertically arranged and fixedly connected to the steel structure upper supporting plate and the steel structure lower supporting plate correspondingly. In this way, according to the I-shaped reinforcing-type steel structure for the building, by adopting the first connecting plate and the second connecting plate, an original I-shaped steel structure is reinforced, the firm degree of the steel structure is further improved, the structure is novel, the performance is stable, the firmness is good, safety and reliability are achieved, convenience and practicability are achieved, and the I-shaped reinforced-type steel structure for the building has wide market prospects on popularization.