The invention discloses an adaptive weight grounding line selection method based on wavelet singular information. The method comprises the following steps: S1, recording a zero-sequence current sequence between a current cycle before a fault and two current cycles after the fault of each path of outgoing line through a fault recorder; s2, performing normalization processing on the zero-sequence current sequence; s3, calculating a wavelet singular information vector corresponding to the zero-sequence current sequence after normalization processing; s4, calculating wavelet singular values, corresponding to different scales, of all outgoing lines, and building a self-adaptive weight comprehensive measurement evaluation function in combination with the wavelet singular information vectors; andS5, calculating a self-adaptive weight comprehensive measurement evaluation function value corresponding to each outgoing line through the self-adaptive weight comprehensive measure evaluation function, and selecting a line with a single-phase earth fault. The method can adapt to different fault working conditions, has high capabilities of resisting factors such as transition resistance, fault phase angle and fault distance, and is accurate and reliable in line selection.