In order to investigate the icing condition of the transmission line which across the Micro-Geography (MG) and Micro-Meteorological (MM), in this paper, on the basis of micro-climate theory, the regression model between meteorological factors is established by the multiple regression analysis method, taking three transmission lines which with typical micro-topography distribution in North China Grid and occurred accidents in history as an example. The results show that the method can reveal the relationship between micro-meteorological parameters from a quantitative angle and make the meteorological analysis and prediction of transmission lines in micro-geography environment more accurately. It lay a foundation for real-time evaluation of electrical reliability of transmission lines and the establishment of early warning system. This work is supported by Science and Technology Project of State Grid Tianjin Electric Power Company (Research on Prediction Technology of Transmission Lines Wet Snow Flash in Coastal Heavy Pollution Areas, No. KJ19-1-07).