The invention provides a same-rod double-loop-line phase selection method based on single loop lien information. On the condition that a line fault occurs, the following phase selection steps are performed: (1), utilizing an electric amount of a single loop line; (2), determining whether a negative-sequence voltage U2 at a protected mounting part; (3), according to whether the negative-sequence voltage U0 at the protected mounting part is zero, distinguishing two fault types, namely a synonym over-line non-grounding fault and other fault types; (4), identifying the fault type according to a relation between sequence impedances deltaZ1 and Z2 at the protected mounting part; (5), according to a relation between deltaZ1 and a system positive-sequence impedance ZMS1, distinguishing each type in near-end fault types 2, 3, 4 and fault phase; and (6), determining the fault type and the fault phase according to opposite-end information. The same-rod double-loop-line phase selection method has advantages of high versatility so that the method is suitable for various operation modes of double loop lines; high flexibility; accurate phase selection result for facilitating impedance calculation, fault ranging, reclosing and the like; and relatively high reliability.