Abstract: In order to assess demand judgment of distribution networks voltage, the concept, evaluation criteria and quantitative evaluation system of distribution networks voltage are presented to improve voltage potential of distribution networks in the paper. The nodal at the end of the trunk feeder of distribution lines is used as assessment node, and its voltage profile is regarded as a criterion. The voltage improving potential is calculated by suitable technique and measures under the static load flow of typical operation mode, which is defined as the voltage improving potential. The assessment system of voltage improving potential is proposed based on micro-macro (distribution lines-large-scale distribution network) model. Taking the mode of distributed micro calculation and centralized macro assessment, by static analysis on voltage improving potential of classified typical lines under different measures, total voltage improving potential of distribution networks is assessed quantitively. The proposed method can be used to realize the macro quantitative evaluation for voltage optimization within the planning, operation and management domain of distribution systems. Example shows that the comprehensive application of a variety of measures can fully tap voltage improving potential of lines.