An electronic device includes a printed circuit board, an electronic element, and a backboard assembly. The printed circuit board defines a plurality of first through holes. The electronic element is mounted on a top surface of the printed circuit board. The backboard is assembly secured to a bottom surface of the printed circuit board. The backboard assembly includes a back plate, an electrically insulative sheet, and a connection element. The electrically insulative sheet defines a plurality of second through holes. The connection element includes a plurality of first engaging structures on a first side thereof to engage with the back plate and a plurality of first clasps on a second side of the connection element opposing to the first side to engage with the electrically insulative sheet.