The invention discloses a method for identifying a lightning stroke fault and a non-lightning stroke fault of a transmission line. The method comprises the following steps of utilizing a high-speed data acquiring device to sample and record three-phase transient current on a transmission line in real time, comparing the maximum amplitude of the three-phase transient current at the same observation point, identifying the fault phase, analyzing the starting time and wave tail time of the fault phase current, calculating the wave tail time, and comparing the wave tail time with a set threshold value, and identifying whether the fault is a lightning stroke fault or a non-lightning stroke fault. In the past, the method for identifying the fault type by utilizing a power frequency voltage is usually influenced by the load current, line length and transition resistance. Based on the fault high frequency transient signal, the method provided by the invention has the characteristics of being free from the influences of the line load current, line length and transition resistance, and moreover, the method has the advantages of simple criterion and easiness in realizing.