Based on the characteristics of mixed lines composed by four-circuit lines and double-circuit lines on the same tower, the corresponding inverted-sequence positive sequence networks are proposed. on the basis, this paper combines with negative current and positive current and uses the relationship that the negative and positive voltage from bus beginning terminal of fault branch to fault point is equal to the voltage from the T branch node to fault point to derive the fault location equation. According to the solution of the equation, its fault side and fault locating are detected simultaneously. Results of PSCAD/EMTDC simulation verify that the new scheme is accurate and not influenced by fault type, transition resistance, system operating mode and other factors on locating precision.