This application provides a power supply method for a data center. The data center includes a first device and at least one second device, an importance of a first service in the first device is higher than an importance of a second service in the at least one second device, and the second service in the at least one second device is transferable. A power supply apparatus includes a first uninterruptible power supply UPS and a second UPS, the first UPS is configured to control a first power source and a first energy storage apparatus to supply power to the first device, and the second UPS is configured to control the first power source and a second energy storage apparatus to supply power to the at least one second device.