Based on the detailed analysis of SLG fault characteristics in the small current grounding system, an adaptive multi-criteria fusion algorithm based on transient signal for fault line selection is proposed in this paper. The algorithm introduces fault membership and criterion confidence to achieve the fusion of multiple transient fault line selection criteria. At the same time, each criterion adaptively determines whether to participate in this line selection according to its confidence level. Matlab/Simulink simulation results indicate that this fault line selection algorithm is not influenced by such factors as the transient characteristics of the fault, fault resistance, length of the faulted line, etc.