The invention discloses a novel transformer-free power quality comprehensive regulator control strategy, which comprises a series-side control strategy and a parallel-side control strategy independent mutually. The strategy particularly comprises the following steps: load AC voltage and voltage after transmission line losses are measured to obtain compensation voltage of a series voltage source-type inverter; with tracking the compensation voltage of the series voltage source-type inverter as a target, a voltage reference value is given, a modulation ratio is obtained, and functions of low voltage boost or overvoltage drop can be realized; nonlinear three-phase asymmetrical load current in an AC distribution network is measured, three-phase voltage at a grid-connected port of a parallel-side voltage source-type inverter is measured, voltage at the outlet end of the transformer and each phase angle are measured, and the grid-connected current reference value of the parallel voltage source-type inverter is solved; and compensation current corresponding to each phase is obtained through pulse width modulation control, and a function of grid-side three-phase current balancing is realized.