A server cabinet includes a rack and a plurality of I/O modules received in the rack. The rack defines an interior space for accommodating a plurality of servers therein. Each server includes a plurality of I/O ports at an outer side thereof. Each of the I/O modules includes a casing, a driving mechanism received in the casing and a plurality of I/O sockets. A plurality of apertures corresponding to the I/O sockets are defined in one side of the casing. The driving mechanism is configured for controlling the I/O sockets telescopically move out of the casing through the apertures or back to the casing. The I/O sockets of each of the I/O modules is configured to electrically connect the I/O ports of each of the servers, respectively, when the I/O sockets are out of the casing.