The invention provides a UPQC control method and device based on coordinated power allocation. The invention first proposes a UPQC power control strategy based on the principle of capacity equalization, so that series and parallel converters share the load power equally, thereby giving full play to the series converter. At the same time, considering that when the voltage of a power supply drops too much, an active circulating current of a system increases, thereby increasing the capacity load and loss of the series and parallel converters, the invention further proposes a UPQC power control strategy based on reactive compensation in the case where the voltage of the power supply drops too much, a compensation voltage phasor of the series converter is controlled to be always perpendicular to a power supply current phasor so that the series converter only emits reactive power, the parallel converter absorbs energy from a DC side energy storage unit and shares the load active power with the power supply, the purpose of eliminating the active circulating current is thus achieved, and at this time, the reactive power output by the series and parallel converters still follows the principle of equalization.