The invention discloses a power transmission line waving track measuring method based on a light curtain sensor. The method sequentially comprises the following steps of A, collecting the moving track during the power transmission line waving; B, collecting time for emitting light beams, by each transverse optoelectronic switch and each longitudinal optoelectronic switch, cut in the power transmission line waving process, and respectively recording the time into number sets T and T; C, calculating the time differences delta T and delta T of the twice adjacent transverse and longitudinal optoelectronic switch cutting; D, calculating the transverse speed V and the longitudinal speed V; E, calculating the waving displacement of a power transmission line in each cutting process; F, drawing the waving track of the power transmission line. The power transmission line waving track measuring method has the advantages that the high-sensitivity outdoor power transmission line waving track measurement can be realized by the light curtain sensor, the measurement precision is high, and meanwhile, the continuity and the completeness of the power transmission line waving track measurement are also ensured.