The invention relates to an inner tensioning pre-stressed concrete single-layer I-shaped framework box-type structure of a building. A framework structure is arranged in the section direction to form a box-type section. The sections of framework beams are I-shaped, and the span range of the peripheral framework beams is 7 to 36 meters. Prestressed ribs are arranged in the framework, and tensioning grooves are reserved on the lateral surfaces of web plates of the framework beams in the structure; and when concrete reaches the specified strength, the segments of the same prestressed rib bundle are sequentially connected end to end through middle anchors at the tensioning grooves and tensioned, and then the tensioning grooves are plugged. The structure is characterized in that the tensioning grooves are reserved on the sections of the framework beam web plates which have low stress and facilitate construction in the structure, and the prestressed ribs are connected through the middle anchors and tensioned in the tensioning grooves. The structure has the advantages that when the ends of the structural member do not have tensioning and anchoring conditions, connection and tensioning of the prestressed ribs can be realized, high comfort degree, using performance and structural performance can be provided, and the structure is particularly suitable to be used as an underground heavy-duty and large-span single-layer framework box-type structure.