The invention provides a recognition method for the lightning stroke category of an electric transmission line. The method comprises the following steps: S1: selecting a lightning wire of an electric transmission line and arranging monitoring and sampling sites at peripheral positions of a three-phase wire, and then collecting the magnetic field intensity of each detection sampling site in real time; S2: comparing the collected magnetic field intensity of each detection sampling site with a corresponding initial value or a preset value; judging the lightning stroke category according to the change of the lightning wire and the magnetic field intensity at the periphery of the three-phase wire as well as preset rules; and outputting corresponding results; and S3: repeating step S2 until reaching the preset maximal calculation time.