A server includes a case, a storage module, a connection module, a first expander board, a second expander board, a first mother board and a second mother board. The case includes a bottom case. The storage module is disposed on the bottom case and includes multiple storage units. The connection module is disposed on the bottom case and connected to the storage module. At least one first expander chip is disposed on the first expander board. At least one second expander chip is disposed on the second expander board. At least one first central processing unit is disposed on the first mother board. At least one second central processing unit is disposed on the second mother board. The first expander board, the second expander board, the first mother board and the second mother board are pluggably connected to the connection module, respectively.