The invention relates to a line selection method for a single-phase disconnection fault of a power distribution network. The method comprises the following steps of analyzing a topological structure of a distribution network system, collecting voltage and current at a line outlet, calculating the abrupt change amount of positive sequence current of a line, comparing the abrupt change amount of thepositive sequence current of the line with a graph variable threshold value of the positive sequence current, calculating the abrupt change amount of positive sequence voltage of the line, and comparing the abrupt change amount of the positive sequence voltage with an abrupt change amount threshold value of the positive sequence voltage; calculating a line impedance, comparing the line impedancewith a line impedance threshold value to obtain fault path lines, and finally selecting the lowest line in the middle level of the fault path lines as the faulted line. The method has the advantages that the fault line patrol time can be greatly shortened, correspondingly convenience is brought for emergency fault correction and fault recovery, power failure time of the lines is shortened, and thepower supply reliability of the power distribution network is improved.