The invention discloses a fault feature analysis based single-phase earth fault line selection method of a medium-voltage distribution network, which comprises the following steps of: calculating a neutral point voltage; judging whether the neutral point voltage exceeds a set threshold; calculating fault features and discriminating fault types, wherein the fault features are defined to be a transient state, a transient steady state and a steady state; judging whether the fault is a single-phase earth fault; positioning a line selection interval; carrying out line selection on the fault; and outputting a result. The fault feature analysis based ingle-phase earth fault line selection method of the medium-voltage distribution network can reflect the development and evolution process of the fault visually and essentially, effectively select lines on stable earthing with the single-phase earth fault time longer than 500 milliseconds, and completely capture and describe the transient faults in the fault process.