Plants and microorganisms are the main components of wetland ecosystems and important drivers of energy flow and material cycling. Understanding the diversity of plants and soil microorganisms and their influencing factors is important for maintaining the structure and function of wetland ecosystems. In this study, we conducted a field investigation and laboratory analysis of 26 Tibetan Plateau wetlands to reveal the relationship between wetland plant diversity and soil bacterial diversity, and to identify key factors affecting both. Results showed that plant diversity was significantly related to soil bacterial diversity, but the main factors driving changes in soil bacterial diversity were environmental factors rather than plants. Plant diversity was mainly affected by soil electrical conductivity, while soil bacterial diversity was influenced by altitude, mean annual precipitation, soil pH, and plant functional traits (leaf carbon content and nitrogen content).