The real mountains are rugged and complex. The slopes on both sides of the ridge line are generally different, showing obvious asymmetry. To better reflect the terrain and wind field effects of real mountains, a simplified model of the cosine-shaped mountain range with variable cross-section is proposed based on the cosine-shaped mountain range. Based on Computational Fluid Dynamics（CFD）numerical simulation, the horizontal mean wind speed-up ratio is compared between the real mountain range, the cosine-shaped mountain range, and the variable cross-section cosine-shaped mountain range in the wind direction parallel to the mountains. The rigid rod method is used to calculate the wind-induced swing response of transmission lines at different positions. The results show that the horizontal mean wind speed-up ratios in the terrain feature points are consistent between the variable cross section cosine-shaped mountain range and the real mountain range. At 50 m above the ground, the horizontal mean wind speed-up ratio along the ridge line of the variable cross-section cosine-shaped mountain range is basically the same as that of the real mountain range. Due to the limitation of parameters, the trend of the ridge line of the cosineshaped mountain range is relatively independent, and its horizontal mean wind speed-up ratio is quite different from that of the real mountain range. The wind-induced swing calculated by variable cross-section cosine-shaped mountain range can much better reflect that of the real mountain range. Although the vertical wind speed of the variable cross-section cosine-shaped mountain range is quite different from that of the real mountain range, the former can better reflect the horizontal mean wind field of the latter. The proposed simplified model has similar wind field effects.