Mounting structure and bath heater

The utility model discloses an installation structure which comprises a first connecting piece, a second connecting piece and a fastening piece. The first connecting piece comprises a mounting plate main body, the mounting plate main body is provided with a first mounting plane, a second mounting plane, a through hole and raised lines, the raised lines surround the through hole and are arranged on the first mounting plane in a protruding manner, and open grooves are formed between the raised lines; the second connecting piece comprises a bottom plate, a side wall and a convex column, the convex column is close to or tightly attached to the side wall, and a cylindrical hole is formed in the convex column; the fastener comprises a column body and a cap body, the column body penetrates through the through hole and is fixed in the cylindrical hole, and the cap body is pressed on the protruding strip. According to the mounting structure, an arc-shaped convex strip is arranged on a first mounting plane of a first c