The invention discloses a welding-free quick assembly supporting structure with grid steel frames for tunnel primary supporting construction. The welding-free quick assembly supporting structure comprises a plurality of grid steel arch frames. The grid steel arch frames are longitudinally arranged along tunnels at intervals, and each grid steel arch frame is anchored on the walls of the corresponding tunnel by foot locking anchor pipe connecting devices; the adjacent grid steel arch frames are connected with one another by longitudinal connecting devices. The welding-free quick assembly supporting structure has the advantages that the welding-free quick assembly supporting structure is simple and is convenient to mount and use, the grid steel arch frames are spliced and connected with the longitudinal connecting devices and foot locking devices, accordingly, welding can be omitted, and related problems of low construction speeds, pollution, difficulty in guaranteeing quality and the like due to welding can be solved; steel plates are preliminarily welded on the grid steel arch frames, holes are reserved in the steel plates, guide hole drilling can be carried out by the aid of the holes, and accordingly construction can be facilitated.