The Qinghai-Tibet Plateau has been an important ecological security barrier area and high-altitude pastoral area in Asia. It is rich in biodiversity resources and fragile ecological environment,and is sensitive to climate change and human activities. This study conducted plantcommunity surveys and sampling across different latitudes and altitudes (3,000-5,000 m) on the Qinghai-Tibet Plateau. The measurements included species diversity,functional diversity,and above ground biomass. Additionally,calculations were performed to determine the multi-year mean values,multi-year change rates,and variation coefficients of monthly mean temperature and precipitation,along with the landscape diversity index to reflect the ecosystem's type diversity in the sampling area. The analysis aimed to reveal the relationship between plant diversity and the productivity of grassland under large-scale environmental gradients. Findings based on the assessment of environmental changes and functional traits indicate the following: (1) The trend of warming and drying is obvious in southern Tibet and near Namtso. The variability of precipitation in the marsh meadow near Namtso Lake and the grassland temperature variability in the alpine grassland of the Qinghai southeastern were high. The mountainous meadow of forest-grassland ecotone in the Qilian Mountains showed the highest diversity among the sampling sites. (2) The plant height and average leaf coverage per plant demonstrated consistent response to climatic factors and landscape diversity,with the former being more sensitive. Climate factor variations exhibited a negative correlation with plant height and leaf coverage,while locations with high landscape diversity displayed higher plant height and leaf coverage. (3) Sites with high variability of climate factors had lower functional diversity,weighted average plant height,and leaf coverage in the community. This implies that an unstable climate environment reduces the level of community diversity. Higher change rates of climate factors were associated with increased levels of functional diversity,reflecting the adaptive process of grassland plant communities in stabilizing themselves through diversified species functional traits under accelerated environmental change. (4) Landscape diversity exhibited a positive correlation with species diversity and grassland biomass,indicating that the diversity of the grassland landscape diversity promotes species diversity and biomass accumulation. (5) Most plant diversity indexes demonstrated a direct proportionality with grassland biomass,confirming the positive effect of grassland diversity on productivity. Our study contributes in understanding the formation and influencing factors of biodiversity patterns in alpine steppe under different gradient climate and landscape environments on the Qinghai-Tibet Plateau. Moreover,it provides a theoretical basis and valuable references for studying diversity protection under environmental change and informing decision-making processes.