Abstract: The wind environment of high voltage transmission lines in the mountain range is of great importance for the refined design and safe operation of transmission lines, especially in the northwest. Taking the Helan Mountains as the object of study, the differences in wind environmental characteristics such as the form of wind speed probability density distribution, mean/standard deviation of wind speed fluctuation and correlation of wind speed fluctuation at different locations in the Helan Mountains are investigated through statistical analysis of historical daily average wind speed data at different locations in the mountain range. Further, the feasibility of using wind speed correlation to predict wind speed in other regions based on observation data from a certain location is explored. The results show that the daily mean wind speed probability density distributions at different locations in the mountain range all exhibit asymmetric single-peaked distribution characteristics, i.e. the differences in the form of daily mean wind speed probability density distributions in the mountain range are not significant. However, in terms of mean and standard deviation of daily mean wind speed fluctuations, the influence of mountains is more pronounced, i.e. the mean and standard deviation of daily mean wind speed fluctuations are greatest on the slopes of mountains, followed by the mean and standard deviation of daily mean wind speed fluctuations at the foot of mountains with ravine windway type microtopography, and the mean and standard deviation of daily mean wind speed fluctuations at the foot of mountains and away from mountains are the smallest. In terms of the correlation between the daily mean wind speed fluctuations, there is a difference in the intensity of the daily mean wind speed at the foot of the mountain and on the slope, but the difference in the nature of the fluctuations is relatively small. In other words, for the slopes and foothills of mountains, the influence of the mountains on the intensity of the wind speed is greater than the fluctuating nature. The correlation between the daily mean wind speed fluctuations at distant locations from the mountains and the slope is poor. This suggests that the presence of mountains not only affects the intensity of wind speed, but also the nature of the daily mean wind speed fluctuation. It can be seen that the presence of mountains has an important influence on the intensity and fluctuating nature of the daily average wind speed. At the same time, the quantitative prediction of wind speed in different regions can be achieved based on the correlation of wind speed at different locations of the mountain.