The current of single-phase grounding fault in NUGS is very small, so correctly detecting earthing fault line is hard to achieve on the system with insulated neutral point. The existing different grounding fault line selecting methods have some limitations and shortcomings and lack credibility. In order to solve the problem, in the paper comprehensively various methods method of each fault detection in small current grounding system based on information fusion and intelligent process is proposed , and select fault line many times, achieve the desired effect of fault locating. A multi-criteria fault line selecting method is presented by using information fusion and intelligent process is proposed. A fuzzy comprehensive evaluation is given. The simulation results show the proposed method of fuzzy data fusion from multiple line selecting has higher credibility.