An uninterruptible power supply system (UPS) and a power management method thereof suitable for an audio visual apparatus are provided. The uninterruptible power supply system includes a power management unit, a wireless transceiver module and a current detecting unit, wherein the current detecting unit is coupled to an output of the power management unit to detect a load current output from the UPS system. The UPS is capable of receiving and learning a wireless command code in an infrared ray (IR) remote control signal. When the UPS system detects a multimedia system connected thereto is turned on and the UPS system is in a lower power state, the UPS system sends command code to turn off the multimedia system to avoid the damage of the multimedia system during power failure.