Most of the cable faults are related to metal sheath, only considering the structural parameters of the guide core electrical model cannot realize the fault location of the protective layer. In order to solve the problem of distribution network single-phase cable fault location difficulties, a single terminal fault location method for cable single phase fault based on metal sheath model parameter identification is proposed. This paper first takes the single-phase distribution network fault zero mold equivalent network as the identification model, and fault distance, fault resistance, and capacitance to ground as the unknown parameters of the model, then uses the transient information cable after the single-phase grounding fault cable core and sheath and combines the fault state network and zero mold equivalent model to establish the time-domain ranging equation as a parameter the identification of the objective function, finally applies the least-square algorithm to solve the optimal parameters, obtaining the fault distance. ATP-EMTP simulation results verify the effectiveness of the proposed method, and the ranging accuracy is high. This work is supported by National Natural Science Foundation of China (No. 51477147).