The invention discloses a meteorological associated power transmission line risk difference evaluation method. Based on the factors such as area power grid meteorological sensitivity, area line fault frequency difference, area line fault out-of-service time difference, line fault high risk section, etc., the method can perform power transmission line fault area characteristic difference evaluation through an area power grid meteorological sensitivity index, an area line fault frequency difference index, and a line fault high risk section index, and perform power transmission line fault time characteristic difference evaluation through a historic same period monthly fault frequency index, an outage time index under different meteorological calamity effects, a fault time interval index and a short time fault concentration degree index. The method can fully disclose line out-of-service risk difference characteristics in a target area, completely reflect a meteorological calamity influence rule and a line disaster prevention and disaster resistance capability, and be helpful for controlling power grid operation risks specially, and improving electric power system operational reliability.