A power management system includes a smart socket to meter power consumption of an electric device by connecting to the electric device, and be assigned a code, a power management apparatus to display a code image when a registration mode of the smart socket is performed, and a terminal to acquire a code image of the power management apparatus and a code image of the smart socket, receive information of an electric device to be coupled to the smart socket, read the acquired code images of the power management apparatus and the smart socket, pair the read power management apparatus and the smart socket code with the electric device information, and transmit the paired information to the power management apparatus. Users of all ages and dexterity can easily register, change, and release the smart socket and the electric device, such that user efficiency and accessibility are increased.