Hidden connecting piece

The utility model belongs to the field of connecting pieces, and discloses a hidden connecting piece which comprises a first embedded part, a second embedded part and a top block, and an expansion locking part is composed of a plurality of expansion pieces. First sawteeth which are arranged in multiple layers are arranged in each expansion piece, and second sawteeth which are arranged in multiple layers are arranged outside each expansion piece; the top block comprises a bottom plate, a center column and a plurality of partition plates distributed on the periphery of the center column. The partition plates are used for being embedded between the adjacent expansion pieces. The center column is provided with third sawteeth arranged in a multi-layer mode, and the third sawteeth are meshed with the first sawteeth. The connecting module is mounted on one embedded part of the connecting piece, and the expansion locking part is mounted on the other embedded part, so that the processing difficulty is lower; meanwhile