Abstract: Plants play a pivotal role in shaping wetland ecosystems and soil nitrogen dynamics by modifying the soil microenvironment, releasing rhizosphere exudates, and influencing microbial processes. To clarify the effects of vegetation characteristics on nitrogen transformation rates and associated microbial functional gene abundance, rhizosphere and bulk soil samples were collected from 26 representative wetlands on the Qinghai-Tibet Plateau. Key nitrogen transformation parameters, including net nitrogen mineralization rate (NMR), potential nitrification rate (PNR), net nitrification rate (NNR), potential denitrification rate (PDR), background denitrification rate (UDR), and N₂O production rate, were quantified. In parallel, the absolute abundances of gdhA, amoA, norB, and 16S rRNA genes were measured using quantitative real-time polymerase chain reaction (PCR). Results showed that: (1) Rhizosphere soils exhibited significantly higher NMR and PDR but lower PNR compared to bulk soils. Additionally, rhizosphere soils harbored significantly greater abundances of gdhA, amoA, norB, and 16S rRNA genes. (2) NMR was significantly positively correlated with aboveground biomass and specific leaf area but negatively correlated with leaf total nitrogen content. PNR was significantly positively correlated with the Simpson index, while NNR was significantly negatively correlated with leaf total phosphorus content. UDR was significantly positively correlated with the Pielou index. (3) Structural relationships further revealed that plant biomass directly affected nitrogen mineralization and indirectly modulated this process via alterations in soil physicochemical properties. Plant biomass and functional traits also indirectly regulated nitrification and denitrification via soil physical and chemical pathways. These findings highlight the regulatory role of vegetation characteristics in mediating soil nitrogen transformation and functional gene abundance, underscoring the importance of integrating plant traits into assessments of nitrogen cycling mechanisms and management strategies in alpine wetlands.