Distribution automation can effectively improve power supply reliability, but the balance between efficiency and investment reliability must be taken into account. Considering the reliability and investment of distribution automation, this paper establishes the model of net income after the implementation of distribution automation, which contains an improved algorithm of minimum cut sets of load point and fault repair time mathematical model under the condition of distribution automation. Combined with the power supply area designated by the classification of State Grid Corporation of China, it puts forward the best distribution automation solution suitable for differentiation of each power supply division. Research suggests that in the area of B power supply, two kinds of distribution automation technology are recommended:feeder automation based on recloser and sectionalizer, intelligent control method based on distributed protection terminal. In the area of A power supply which the ratio of value to unit electric energy consumption is greater than 15, intelligent control method based on distributed protection terminal is recommended. For areas with developed economies, high load density, and high reliability requirements, distribution automation system is recommended and the range of the ratio of value to unit electric energy consumption is provided.