The threephase load imbalance seriously influences the safety, economic and reliable operation of distribution network. On this background, a control strategy of the SCR is proposed in this paper. Firstly, on the basis of the seamless commutation device, a mathematic model of threephase load imbalance treatment system in distribution network is established. Then, the vectorgenetic algorithm is utiliazed to realize the threephase load imbalance treatment and the optimal phase allocation scheme of the distribution area is obtained. Finally, the feasibility of the algorithm is verified by the simulation. The seamless commutation devices are installed in the low voltage distribution area and the experimental results validate the correctness and feasibility of the proposed control scheme.