A road structure reconstructed from large-scale independent underground garage and a construction method, which solves the problem of a newly constructed urban expressway passing through large underground space. The technical point is a construction method for the road structure reconstructed from large-scale independent underground garage, including the following steps: S100: segmentation for the garage, S200: preparation before construction: the materials and equipment required for construction are transported to the site, and the construction site is cleaned, S300: reconstruction for the front section, S400: reconstruction for the middle section, S500: reconstruction for the rear section. The inventiveness of the present disclosure is the application of segmentation construction, the front section is completely obsoleted, a transition section is provided at the middle, and the design of the rear section adopts a double-deck road, thus the original underground garage structure is fully utilized.