An uninterruptible power supply apparatus and method. The uninterruptible power supply apparatus includes a first generator, an energy storage, a first power converter connected to the energy storage, a second power converter connected to the energy storage, a first switch connected to the first power converter and a first load, a second switch connected to the second power converter, the first generator and a second load, and a third switch connected to a power grid, the first generator, the second power converter, the first switch and the second switch. In a normal state in which the first switch and the third switch are connected, the power grid supplies power to the first load or the second load. In an independent operating state in which the third switch is turned off, the first generator or the energy storage uninterruptibly supplies power to the first load or the second load.