Abstract: A bi-directional penetrating metal bottleneck structure of a type IV hydrogen storage tank is provided, which includes a metal valve seat, a plastic liner, and a fiber winding layer. A valve seat hole is formed on an inner side of the metal valve seat, and the metal valve seat includes an annular flange, a valve seat column section, and a valve seat extension. L-shaped through holes and radial penetrating holes are formed in the valve seat column section. The valve seat hole is an irregular through hole and is provided with an annular groove. The valve seat extension is provided with a winding inclined plane, a self-tightening conical surface, a circumferential groove, and axial penetrating holes. The plastic liner includes an inner plastic joint, an outer plastic joint, a tapered connecting section, L-shaped connectors, radial connectors, axial connectors, and a reinforcement section.