The invention discloses a broken line identification method based on comparison of zero-sequence voltage differential values. A three-phase voltage of a bus and a three-phase current of each outgoing line are collected in a transformer station, an abrupt change value of the three-phase voltage amplitude and an amplitude of the three-phase current of each outgoing line are calculated on the basis of the three-phase voltage and currents, a zero-sequence voltage of the bus and a zero-sequence voltage of the high voltage side of a transformer of the power distribution network are calculated, zero-sequence voltage differential values of the outgoing lines are calculated, the magnitudes of the zero-sequence voltage differential values of all the outgoing lines are compared, and the outgoing line whose zero-sequence voltage differential value is highest is a fault line. According to the invention, only information of the transformer station is used, influence of a neutral point grounding manner and a broken line position of the power distribution network is avoided, a broken line not-grounding fault and a broken line loaded-side grounding fault can be identified reliably, and the power supply reliability of the power distribution network is improved effectively.