Abstract: Grasslands in Qilian Mountains plays an important role in maintaining the ecological security of western China. To understand soil physical and chemical properties and the distribution characteristics of vegetation, as well as their correlation in different types of grasslands in Qilian Mountains, we measured soil moisture, nutrient content, bulk density, particle composition, and vegetation characteristics in seven types of grassland in Qilian Mountains. The fractal dimension of soil particles, soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm soil layer, and plant diversity index were calculated. The results showed that there were significant differences in soil physical and chemical properties and vegetation characteristics among different grassland types. Compared with other types of grassland, alpine meadow had higher soil water, nutrient and clay content, but lower bulk density and sand content. Soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm layer ranged from 3084 to 45247, 164 to 2358 and 100 to 319 g·m^-2, respectively, with high contents of organic carbon and total nitrogen and low content of total phosphorus. There was a significant positive correlation between soil total phosphorus storage and plant diversity index, indicating that soil total phosphorus content was the key factor affec-ting grassland plant diversity in Qilian Mountains. Compared with other grassland types, alpine meadow in Qilian Mountains had better vegetation status, soil moisture, and nutrient conditions.

Key words: Qilian Mountains, alpine region, grassland, plant diversity, soil physical property, soil nutrient