A mounting apparatus for mounting a slide rail to a bracket with through holes includes a retaining member and a locking member fixed to the retaining member. The retaining member includes a positioning portion, and defines a through slot. The locking member includes an engaging portion and an operating portion extending through the through slot. The positioning portion engages in a through hole of the bracket from a first side of the bracket, the engaging portion engages with a second side of the bracket. When releasing the slide rail from the bracket, the operating portion is operated to deform the locking member to make the engaging portion be disengaged from the second side of the bracket, and the positioning portion is readily released from the through hole of the bracket, to release the retaining member from the bracket.