Abstract: The present invention provides a clasp assembly for a metallic watch chain, mainly comprising: an inner bend plate, an outer bend plate, and a clasp cap. Said inner bend plate can fit into the narrow groove of the outer bend plate. A convex clasp is disposed on the inner bend plate and corresponds to a concave clasp disposed on the outer bend plate in shape, position and size, and the two clasps engage with each other. The lock and release of the convex and concave clasps causes the lock and release of the watch chain. The clasp cap pivotably connects with the inner bend plate through screws. The hole of the clasp cap connects with the watch chain, and the outer bend plate connects with the watch chain through the cylindrical bodies at the left end. The structure of the clasp assembly is simple and is easy to use.