A server is disclosed, which includes two dividing plates disposed between the side plates, several rails disposed on the side plates and the dividing plates, at least one adapter board module, and several main boards. The dividing plates are parallel to the side plates. Each dividing plate has a position pin. The rails are parallel to the bottom plate. The main boards are slid in the rails. The adapter board module has a support piece and an adapter board. The support piece has position holes to be coupled to the position pins and fix the adapter board module on the dividing plates. The adapter board is disposed on the support piece and has two first gold finger interfaces. Each main board has a second gold finger interface. The first gold finger interfaces are coupled to the second gold finger interfaces, thereby each adapter board is connected to two main boards.