A dynamic current injection method for an asymmetric dynamic current source relates to a distribution network fault detection technology. The trigger sequence, waveform analysis, dynamic and steady-state performance and master of closed-loop control of circuits of corresponding structures are given according to different topologies of a multilevel current source converter; and a current signal with obvious characteristics is generated on a faulty line and a loop is formed through dynamic current injection according to the dynamic response, and maintenance is performed according to a fault indicator in the line. According to the invention, a current signal with obvious characteristics is generated on a faulty line and a loop is formed through dynamic current injection, and the fault is detected according to a fault indicator in the line.