A socket assembly mounted on a printed circuit board comprises a socket mounted upon the printed circuit board; a metal backplane, mounted below the printed circuit board and configured with a board-like shape; and an insulative sheet. The insulative sheet is sandwiched between the printed circuit board and the metal backplane and is formed with at least one latching portion extending downwardly to latch the metal backplane. The insulative sheet further has a plurality of protruding portions extending upwardly to insert into corresponding circular holes defined on of the printed circuit board.