The invention relates to a method and system for analyzing the fault cause of a distribution network line. The method comprises the steps of obtaining data when a current line fails, and determining afault cause type based on the obtained data when the current line fails and a pre-built fault cause type analysis model; based on the fault cause type and a pre-built fault cause small type analysismodel, determining the cause of a line fault. The invention relates to the method and system for analyzing the fault cause of the distribution network line, the fault cause type is determined based onthe obtained data when the current line fails and the pre-built fault cause type analysis model, based on the fault cause type and the pre-built fault cause small type analysis model, the cause of the line fault is determined, the problem of human judgement affecting the timeliness of fault handling is solved, information related to the fault received by staff in a short time is often not comprehensive, a judgment is made according to the information, and the problem that the accuracy of analysis conclusions is affected is solved.