A mounting apparatus includes a bracket, a first circuit board, a securing member, and a second circuit board. The bracket includes a first sidewall, and an end wall perpendicularly extending from a front end of the first sidewall, for fixing a stop plate of a first expansion card. The first circuit board is mounted to the first sidewall of the bracket adjacent to the end wall. A first expansion slot is installed on the first circuit board for engaging with the first expansion card. The securing member is detachably mounted to the first sidewall behind the first circuit board and away from the end wall, for fixing a stop plate of a second expansion card. The second circuit board is detachably mounted to the first sidewall adjacent to the securing member. A second expansion slot is installed on the second circuit board for engaging with the second expansion card.