A method of fault line selection in the resonant grounding system of distribution network based on the characteristics of the charge-voltage(Q-U) in the transient zero sequence and support vector machine(SVM) is proposed. In order to solve the problem that methods of fault line selection in the distribution network are unreliable, this paper researches the characteristic relationship between charge and voltage in the zero sequence from the point of the fault transients generated by phase-to-earth fault. With the classification algorithm of support vector machine that supports for small sample and taking the correlation coefficients of the charge and voltage in the zero sequence of every feeder as the characteristic input, a set of processes of the fault line selection in the distribution network based on the characteristics of the charge and voltage in the zero sequence is established. A 35 kV simulation model of resonant grounding system is established in the PSCAD/EMTDC. A large number of simulation results show that the method is not affected by fault distance and fault time. Especially, it is still be able to select fault line correctly in the condition of high impedance and arc fault.