An assembly apparatus includes a linkage member defining a first front sliding groove and a first rear sliding groove and a sliding member movably connected to the linkage and defining a second front sliding groove and a second rear sliding groove. The first front sliding groove corresponds to the second front sliding groove, and the first rear sliding groove corresponds to the second rear sliding groove. The assembly apparatus further includes a fixing base defining a curved groove, a control member including a first rotation pin and a second rotation pin, and a fixing pin fixed with respect to the fixing base. The first rotation pin is slidably received in the first and second rear sliding groove, the second rotation pin is slidably received in the curved groove, and the fixing pin is slidably received in the first and second front sliding groove.