The Ultra-high voltage (UHV) and long-span (LS) transmission lines, which have large tower heights and long span distances, are susceptible to wind loads. Wind fragility analysis of these structures is an important method for assessing their reliability against wind. This study, taking an UHV-LS transmission tower in Anhui province as the background, based on random wind vibration response analysis engineering theory and China"s current overhead transmission line loading specification to obtain the structural effect distribution of the LS transmission tower under the action of the wind load, took into account the uncertainty of the structural material parameters to establish the probability distribution of wind load carrying capacity. Additionally, this study used the top of the tower displacement, the corrected angle of the inter-segmental displacement as an indicator of determining the level of performance quantitative modeling, and based on these calculations to obtain the transmission tower wind fragility curve. The results indicated that: the wind effect distribution of the quasi-static transmission tower line system could be obtained by the first time beyond the probability theory; the multiple performance level of the UHV-LS transmission tower line system based on the tower top displacement is more conservative than that based on the modified inter-nodal displacement angle; with the aggravation of the structure damage, the influence of structural uncertainty on the bearing capacity of the structure becomes more obvious; the wind fragility analysis shows that the UHV tower has good wind reliability under the design wind load, but its wind damage shows some brittleness.