The invention discloses an identification method of an indirect lightning strike and a direct lightning flash for a power transmission line based on an OPGW. The method includes: step 1, acquiring lightning stroke signals induced in an OPGW fiber; step 2, determining whether the peak value of the lightning stroke signals is greater than a threshold v1; step 3, determining whether the oscillation frequency of the lightning stroke signals in a wave head nearby period threshold t1 is greater than a threshold A and whether the average oscillation peak value amplitude is greater than a threshold B; step 4, determining whether the energy ratio C of a signal spectrum distribution map of the lightning stroke signals after a frequency threshold f1 is greater than 90%; step 5, determining whether the lightning stroke signals present slow (small damping) oscillation attenuation; step 6, determining whether the duration of the lightning stroke signals is greater than a time threshold t2; and step 7, indicating the direct lightning flash if determination results of steps 2-6 are all yes, and otherwise, indicating the indirect lightning strike. According to the method, technical problems of high cost, complicated installation, and difficult discrimination of the direct lightning flash and the indirect lightning strike are solved.