The invention provides a same-rod double-loop-line phase selection method based on a single-end abrupt change amount. When a fault occurs in a line, the phase selection method comprises the following phase selection steps of (1), utilizing electrical amounts of a single loop line, and on the condition that U2 is not equal with zero, calculating voltage abrupt change amount deltaUAB, deltaUBC and deltaUCA, dividing a six-phase area fault of a double-loop-line fault according to a voltage abrupt change amount amplitude at a protective mounting position; (2), calculating current abrupt change amounts deltaIAB, deltaIBC and deltaICA of the two loop lines, and dividing the further fault of the six-phase area fault of the double-loop-line fault according to a relation between each current abrupt change amount phase and amplitude at the protective mounting position; and (3), on the condition that U2 is zero, determining the fault of the loop-line protecting component by sequence impedance detalZ1 and Z2. 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.