The utility model relates to an inner tension prestressed concrete single-layer T-shaped frame box structure of a building. A frame structure is arranged parallel to a section direction to form a box-shaped section. The span range of a frame beam is 7-36 m. A prestressed rib is arranged in a frame. A tension slot is reserved in the side surface of the frame in the structure. After the concrete reaches the ruled strength, a same prestressed rib bundle is sequentially connected for sections in an end-to-end manner and is also tensioned at the tension slot through a middle anchorage device, and then the tension slot is blocked. The inner tension prestressed concrete single-layer T-shaped frame box structure is characterized in that the tension slot is reserved at a small-stress position convenient for construction on the side surface of the frame in the structure, and is connected with and tensions the prestressed rib through the middle anchorage device. The structure has the advantages that prestressed tension connection can be realized when the end part of a structure component does not have a tension anchorage condition; relatively good comfortableness, usage performance and structure performance can be provided; and the structure is especially suitable for an underground heavy-duty large-span single-layer frame box structure.