The invention discloses a method for distinguishing fault types of a non-transposition same-tower double-circuit line. The method comprises the steps that firstly, when the non-transposition same-tower double-circuit line fails, voltage information and current information at the protection installation position of the non-transposition same-tower double-circuit line are collected in real time through a current transformer and a voltage transformer; secondarily, positive-phase-sequence identical-phase-sequence current components, positive-phase-sequence differential-phase-sequence current components, negative-phase-sequence identical-phase-sequence current components, negative-phase-sequence differential-phase-sequence current components, the zero-phase-sequence identical-phase-sequence current components and zero-phase-sequence differential-phase-sequence current components of the double-circuit line are extracted by using the six-sequence component conversion method, and the relative phase angle between the differential-phase-sequence components and the identical-phase-sequence components of positive-phase-sequence currents and the relative phase angle between the differential-phase-sequence components of negative-phase-sequence currents and the differential-phase-sequence components of the positive-phase-sequence currents are calculated; then whether the non-transposition same-tower double-circuit line has a same-name-phase crossing-line fault or a single-circuit-line fault or a non-same-name-phase crossing-line fault is judged. By means of the method, the single-circuit-line fault, the same-name-phase crossing-line fault and the non-same-name-phase crossing-line fault of the non-transposition same-tower double-circuit line can be distinguished correctly. Excellent fault distinguishing capacity can be still kept when non-transposition parameters and line parameters of the same-tower double-circuit line are seriously unsymmetrical.