The invention discloses a device for controlling three-phase imbalance of a low-voltage power network and a working flow thereof, and aims at solving the problem that the existing three-phase imbalance processing effect is poor. The device comprises an acquisition module, a grounding module, a central processor and a compensation module. The acquisition module, the grounding module and the compensation module are all electrically connected with the central processor. The central processor comprises a database and an analysis and processing module. The analysis and processing module comprises acoarse adjustment module and a fine adjustment module. The acquisition module comprises a current acquisition module, a voltage acquisition module and a load detection module. The coarse adjustment module comprises a commutation switch and a commutation detection module. The fine adjustment module comprises a rectifying module and a voltage regulation module. The real-time three-phase imbalance degree is calculated and then the real-time three-phase imbalance degree is compared with the preset three-phase imbalance degree to determine whether the adjustment is needed. If the adjustment is needed, a solution is automatically obtained so that the device has high intelligence, high processing speed and good processing effect.