A method of load fusion is proposed to achieve the subregional and phased planning of best connection modes in 10 kV distribution system based on model design. The best connection mode of the medium-sized region is obtained before considering small corners, and then the load of these corners is fused into the main region by using the model presented in this paper; finally the best connection of the entire region is obtained through the traditional economy and reliability analysis of connection modes. Calculation and analysis of the designed model shows that the method presented in this paper is able to meet the requirements of urban distribution network planning very well.