A power supply system provides power to a server cabinet, which includes a number of servers. A number of sockets, first and second electrical connecting portions, first and second through holes are arranged on a power connecting board. Each socket includes a first power pin connected to the first electrical connecting portion and a first ground pin connected to the second electrical connecting portion. A number of power interfaces, third and fourth electrical connecting portions, third and fourth through holes are arranged on a base. Each power interface includes a second power pin connected to the third electrical connecting portion and a second ground pin connected to the fourth electrical connecting portion. The base is electrically connected to the power connecting board when the first connecting element engages in the first and third through holes and the second connecting element engages in the second and fourth through holes.