This study systematically explored the relationship between leaf functional traits and environmental factors based on 78 quadrats arranged and 35 dominant species of plants investigated in July 2021 in the Qilian Mountains. The results showed significant differences in plant functional traits among different vegetation types. The average values of the nitrogen balance index (NBI), chlorophyll content (Chl), leaf width (LW), flavonol content (Flv), leaf area (LA), and leaf circumference (LC) for shrubs were lower than those of herbs, while the average values of NBI, LA, Chl, LW, Flv, and LC for trees were lower than those of shrubs. The NBI had an obvious positive relationship with Chl, whether for herbs or shrubs and trees, while the NBI had a significant negative relationship with anthocyanin content (Anth) for herbs. The soil temperature decreased from 0-20 cm (20.26ºC) to 80-100 cm (14.9ºC), and the soil temperature of 60-80 cm was equivalent to 80-100 cm. Compared with herbs, shrubs are tall and have higher requirements for the growth environment. The growth and chlorophyll content of shrubs decreased with an increase in altitude. Like herbs and shrubs, trees had significant altitude differences in cold regions. The direct influencing factors of leaf functional traits of plants are climate and soil conditions in cold regions, while the indirect factors are mainly geospatial variations, local environment, and underlying surface conditions.