The invention discloses a GPU (graphic processing unit) parallel technology based conductor sag calculation method. The method includes steps: step A) acquiring basic parameters in calculation, wherein the basic parameters include meteorological region parameters and conductor parameters; step B) grouping poles and towers into each strain section according to business rules of the power field, respectively calculating pole and tower parameters and span parameters of each strain section according to the basic parameters to obtain the pole and tower parameters and the span parameters of each strain section; step C) adopting a GPU for parallelly calculating conductor stress and conductor sag according to the obtained pole and tower parameters and the span parameters of each strain section. By the principles, parallel processing of mass sag data can be realized, processing speed is greatly increased, data processing accuracy is greatly improved, and the GPU parallel technology based conductor sag calculation method is pretty applicable to rural power distribution networks.