The stochastic nature of single-phase loads exacerbates the three-phase voltage imbalance in low-voltage distribution networks, and the existing three-phase load imbalance control measures for low-voltage distribution networks mainly use two types of phase-change load casting and additional imbalance compensation devices, discontinuity of power supply, long compensation process, and complexity of the system, have made the management of the three-phase voltage imbalance a difficult problem that needs to be solved urgently. This paper proposes and analyses the method of adaptive regulation of Y-△ connection topology power transfer transformer to suppress three-phase unbalance in low-voltage distribution network, simulates and analyses the principle and influencing factors of three-phase unbalance suppression by power transfer transformer, builds a simulation experimental platform based on Y-△ power transfer transformer to suppress three-phase voltage unbalance, and analyses voltage unbalance suppression law under different unbalanced loads. The application of Y-△ coupling transformer in actual transmission lines is also analysed. The experimental and field data show that based on this method, without active control, it can balance three-phase power automatically and in real time, and improve three-phase load imbalance.