Based on distributed parameter model and analysis of differential sequence circuit in Teed line， an accurate fault location algorithm for Teed line is described. Common components and differential components are introduced into the algorithm to decouple mutual electromagnetic effect between lines. Because the differential sequence voltages at fault position are equal， equation can be founded on the basis of analyzing differential positive sequence current. The result of EMTP simulation indicates that the proposed algorithm is not affected by fault resistance and system operating mode. It can also be applied in asymmetrical parallel transmission lines.