In order to realize the traveling wave fault location of the asymmetrical four-parallel transmission lines on the same tower, three impedance decoupling matrices M1, M2, and M3 in different physical meanings have been introduced in this paper. After comparing and analyzing the relative characteristics of each decoupled module component, the M3 has a natural optional line function and the modulo 2, modulo 5, modulo 8 and modulo 11 in the decoupling matrix M3 and the I, II, III, and IV lines are correspond one-to-one. Thereby, the traveling wave fault location of the four-parallel transmission lines can be converted into the single-loop line, which subtly solves the difficult problem of fault traveling wave selection. Through the 3 times B-spline wavelet packet transform analyzes the selected modulus traveling wave to achieve fault detection, and finally, the double-ended traveling wave ranging principle is adopted to complete the location. A large number of PSCAD/EMTDC experimental simulation data show that the ranging result is not affected by the location of the fault point and the transition resistance, which verifies the accuracy of the traveling wave modulus selection and the feasibility of traveling wave fault location.