A seamless back buckle with concealed fittings, including a substrate and a plurality of rows of fittings disposed on the substrate; wherein the substrate includes a surface layer and a bottom layer, an interlayer is disposed between the surface layer and the bottom layer, and the plurality of rows of fittings are disposed in the interlayer; and a through hole is formed at a position corresponding to each fitting on the surface layer, and each through hole is communicated with an interior of the interlayer. A new concealed structure is adopted for the fittings of the back buckle, which provides a new idea for the underwear market, and can effectively simplify production procedures and reduce production costs.