Considering the fault dead time problem of transmission lines with T type branches, a new algorithm based on wavelet energy spectrum for T transmission line location is proposed to achieve fault precision location. The cubic B-spline algorithm of wavelet transform modulus maxima is applied to extract the fault feature. In the non-dead zone, the three-terminal location method is used to accurately complete the fault location. In the dead time range, the wavelet energy spectrum algorithm judges the fault branch, and then the three terminal fault location method is used to complete the fault location. The simulation results show that the proposed method can meet the requirements of T-line fault location. The algorithm proposed in this paper is not only affected by the fault type and transition impedance, but also appropriate to solve the difficult problem of measuring the blind area in an O area.