Abstract: In view of problem of difficult fault line selection for small current grounding system, the paper proposed a fault line selection method for small current grounding system based on multi-source information fusion. Taking fault line set, fault characteristics set of each line and amount domain regulated by fault characteristics of each line as three elements of matter element of extension fusion, taking size of fault angle as weight, the method effectively fuse energy line selection method with accurate line selection under small fault angle and wavelet packet line selection method with accurate line selection under big fault angle, so as to realize accurate line selection combining with reclosing technology. The simulation result validates effectiveness and reasonableness of the method.