In view of the distribution of different frequency in terms of phase-frequency characteristic， the polarity of zero sequence transient current in fault line is demonstrated to be opposite to those in healthy feeders in the selected frequency band（SFB）. Wavelet packet is then used to decompose the zero sequence transient current and the signs of coefficients of wavelet packet represent the polarities of currents in corresponding frequency bands. The decomposition tree nodes of wavelet packet for the most centralized distributing frequency band can be ascertained according to the principle of maximum energy within the SFB. The fault line selection is therefore adaptively done by comparing the polarities of the zero sequence transient currents in all lines at the node containing the each maximum energy. The PSCAD simulation results show that the method proposed can accurately and reliably carry out the fault line selection in hybrid cable-overhead line non-solidly earthed network.