The invention discloses a windage yaw flashover risk assessment method for a power transmission line based on hierarchical analysis - entropy weight combination, and the method comprises the steps: S1, building a windage yaw flashover risk assessment index system; S2, carrying out the subjective and objective assessment of the assessment indexes; S3, calculating an assessment index comprehensive weight value; S4, assessing a windage yaw flashover risk of the power transmission line. According to the invention, the method introduces the influence of weather features in the a windage yaw flashover risk assessment of the power transmission line, achieves the subjective and objective assessment of the assessment indexes through combining the hierarchical analysis method and the entropy weight method, and enables the obtained assessment result to be more accurate and complete.