The state estimation accuracy and the power network reliability are directly affected by the automatic distribution terminals in active distribution network. The characteristics of distribution network measurement configuration are analyzed, the expression of measurement estimation variance is determined by the sensitivity matrix of state estimation, and an average estimation variance index is constituted. The installation order of new measurement devices is determined according to the contribution of the new measurements to the contribution coefficient of the average estimation variance index. The optimal FTU configuration is iteratively solved by weighing the distribution terminal investment index and state estimation variance index as the objective function, with the distribution network reliability and voltage qualified rate etc. as constraint conditions. The economic efficiency, reliability and the influence on state estimation error of distribution network measurement configuration are considered comprehensively. Through the 118-bus example, the optimization process and results in two stages of “three remote” and “two remote” are analyzed, and the feasibility of the algorithm is demonstrated. This work is supported by National Natural Science Foundation of China (No. 61473265) and Science and Technology Project of Zhejiang Electric Power Company (No. 5211NB160006).