The invention relates to a neural line breaking detection and positioning method. The method judges whether disconnection of a neural line occurs through comparison of distribution transformer low-voltage side three-phase current unbalance rate variation amplitude, a distribution transformer low-voltage side phase voltage value and a user side voltage value according to the three-phase current unbalance rate variation amplitude of different moments and in the last three days; and the disconnection position of the neural line is positioned according to a transformer area power supply network topology structure, comparison conditions of end user voltage of different sections and distribution transformer low-voltage side voltage and a GIS map, and a judgment result is pushed to operation and maintenance personnel, so that alarm information is processed in time and related emergency maintenance work is developed. The method provided by the invention is applicable to low-voltage neutral line disconnection detection and fault positioning.