A mounting apparatus includes a first bracket and a second bracket. Two guides are located on the first bracket. A locking block is located on the first bracket between the two guides. The second bracket receives a first fan. Two sliding portions are located on the second bracket and engaged with the two guides. A latch is resiliently deformable and located on the second bracket between the two sliding portions. A plurality of receiving holes is defined in the latch. The second bracket is slidable between the two guides relative to the first bracket. The locking block is can engage in the plurality of receiving holes to secure the first bracket to the second bracket in a plurality of positions.