The plant communities species diversity of alpine-cold grassland in different elevation gradients was studied.Regression analysis was used to study the relationships between 4 diversity indexes and 14 soil factors.Results indicated that total salt content,HCO₃^-,Ca²⁺,available nitrogen,pH,and soil moisture content were correlative to species diversity significantly(P<0.05).The relationship among diversity,total salt content,HCO₃^-,Ca²⁺,available nitrogen,and soil moisture content was best fitted by binomial model.The relationship between pH and richness index was best fitted by linear model.The relationship among Shannon Wiener index,the total salt content,Ca²⁺,and pH was best fitted by binomial model.The relationship between soil moisture content and Shannon Wiener index was best fitted by linear model.The results showed that diversity did not have a simple negative or positive relationship with the soil factors.