Provided is a circuit capable of simultaneously adjusting the quality of electric energy and performing active arc extinguishing on a low-current ground fault. The circuit is characterized by including: a three-phase series module and a first coupling transformer, which are used for keeping voltages of a DC bus steady and inserting voltages into a distribution system line to solve the problem of voltage fluctuation of a power grid; a three-phase parallel module and a second coupling transformer, wherein currents are injected to a distribution system through the second coupling transformer during adjustment of the quality of electric energy to eliminate harmonic wave components of load currents in the line, and zero sequence compensation currents are injected to the distribution system during active compensation arc extinguishing; and a DC bus voltage stabilization unit, which connects the three-phase series module with the three-phase parallel module, and is used for providing steady DC voltages to the DC side of the three-phase series module and the three-phase parallel module. The circuit is capable of simultaneously adjusting the quality of electric energy and performing active arc extinguishing on a low-current ground fault. Through adoption of the three-phase series module, the three-phase parallel module and the DC bus voltage stabilization unit, the functions of simultaneously adjusting the quality of electric energy and performing active compensation on a low-current ground fault are achieved.