With the frequent occurrence of extreme natural disasters, power grid systems are facing increasingly severe challenges. The aim of this study is to analyze the impacts of geohazards on the safe operation of power systems, especially the threats posed to transmission lines. To this end, we constructed a hazard vulnerability map using a logistic regression model based on seven key internal factors, such as DEM, slope direction, slope gradient, road, water system, soil type, and NDVI. In addition, considering precipitation as an external trigger, this paper further combines internal and external factors to construct a geohazard risk mapping. By combining the geographic locations of transmission lines in New England with these maps, we evaluated the hazard factor of each transmission line. The results show that the geohazard risk faced by transmission lines can be effectively predicted and quantified by this method, which provides an important reference for grid planning and disaster prevention and control.