Plant diversity plays an important role in maintaining the stability of ecological functions. Based on field investigation and empirical analysis, this study took the grassland in different vegetation zones of the Loess Plateau as the research object, explored the characteristics of plant diversity and community stability, assessed the relationship between the two indicators, and further revealed the essential drivers that affected the relationships. The results showed that the characteristics of community structure (aboveground biomass, underground biomass) and plant diversity (richness, diversity and evenness) in grassland on the Loess Plateau had an obvious latitudinal distribution pattern, and the diversity and biomass of grassland plant showed the following trend from southeast to northwest:forest steppe belt > forest belt > grassland belt > desert grassland belt. The plant diversity and community stability of grassland in forest steppe belt were significantly higher than those in the other belts; There was a significantly positive correlation between plant diversity and community stability, suggesting that the plant diversity could be used as an index to estimate the stability.The order of stability was forest-steppe belt>forest belt>steppe belt>steppe desert belt. Rainfall was the main factor that influenced plant diversity and community stability, further affecting community stability by changing soil moisture content. The results of this study revealed the relationship between grassland plant diversity and community stability and the underlying driving mechanism, which provided a scientific basis for maintaining the community stability of grassland ecosystem on the Loess Plateau.