The fast and accurate fault line selection of single phase to earth fault in distribution network system is of great significance to the safe operation of power network. To overcome the problem of inaccurate result of traditional fault line selection method which is caused by poor ability to resist noise and influence of the compensation degree of arc suppression coil, a new criterion of fault line selection in resonant grounding system based on multifractal detrended flucuation analysis (MFDFA) is presented in this paper. Using the boundary value ratio ζ to describe distribution features of the zero sequence current fractal parameters feeder curve H(q), the fault line selection based on the numerical difference. Simulation results show that the proposed criterion has the advantages of no filtering, strong antinoise ability, computing speed and overcome the arc suppression coil on the influence of fault line selection and fault conditions.