Abstract: Because the characteristics of wind field in hilly terrain are obviously different from that in flat terrain, the effect of hilly terrain wind field should be considered when analyzing the wind-induced vibration response of the tension suspension-braced transmission structure in hilly terrain. In order to analyze the wind-induced vibration response of the transmission structure in hilly terrain, wind tunnel tests on the characteristics of the hilly terrain wind field are finished at first. On this basis, the variations of the mean velocity speed-up ratio and the fluctuating velocity speed-up ratio with different slope and height of hills are studied, and the calculation models of the mean velocity speed-up ratio and the fluctuating velocity speed-up ratio are proposed. Subsequently, a nonlinear finite element analysis framework of wind-induced vibration for the tension suspension-braced transmission structure is established by the nonlinear finite element method considering the effect of hilly terrain wind field. Finally, a two-span tension suspension-braced transmission structure is selected as an example, and considering the effect of hilly terrain wind field, the wind-induced vibration response is analyzed by the framework proposed. The results indicate that: with the increase of the slope and height of hill, the mean velocity speed-up ratio at the crest gradually increases, and at the foot of the leeward side, the mean velocity speed-up ratio gradually decreases, while the fluctuating velocity speed-up ratio significantly increases.Considering the effect of hilly terrain wind field, the mean value of the midpoint lateral displacement of conductor and supporting-conductor suspension cable decreases greatly, respectively around 20% and 12%, while the mean value of the midpoint tension changes by around 2%.Under the influence of the fluctuating velocity speed-up effect, considering the effect of hilly terrain wind field, the standard deviation of the midpoint lateral displacement and midpoint tension of the conductor and supporting-conductor suspension cable is increasing, with the maximum increase in the conductor midpoint tension, which can reach 14%.