Abstract: A multi-function power converting apparatus including an inverter circuit and a controller is provided. The inverter circuit drives a load. The controller generates a control signal according to a sampled DC voltage, a sampled AC voltage, a load current, and an output current. The controller causes the inverter circuit to enter an uninterruptible power supply mode or a grid-connected power supply mode through the control signal. Specifically, when the inverter circuit enters the grid-connected power supply mode, the multi-function power converting apparatus operates in one of a mixed real-virtual power output mode, a rectification charging mode, an active filtering mode, and an active power balancing mode.