Identifying the structure and diversity of denitrifying microbial community in tropical forest is of great significance for understanding N₂O emissions from soil denitrification as well as for mitigating global warming. In this study, three secondary restoration stages (i.e., Mallotus paniculatus, Millettia leptobotrya, and Syzygium oblatum communities) of Xishuangbanna tropical forests were selected to explore the composition and diversity of nirS-denitrifying microbial community in dry and wet seasons. We also examined the effects of variations in soil physicochemical properties on structure and diversity of nirS-denitrifying bacteria community during tropical forest restoration. Our results showed that the relative abundance of Proteobacteria and Acidobacteria was higher in early recovery stage than in later stage. In contrast, the relative abundance of Dechloromonas, Halomonas, and Rhodanobacter was higher in later stage than in early one. The relative abundance of Chloroflexi and Actinobacteria increased along with the tropical forest restoration, while that of Cupriavidus and Pseudomonas had an opposite tendency. The genus number of nirS-denitrifying bacteria community in September was ranked as S. oblatum (19) > M. paniculatus (13) > M. leptobotrya (7). The order of Shannon diversity of nirS-denitrifying microbial community was S. oblatum > M. leptobotrya > M. paniculatus. The Shannon diversity was higher in wet season (September) than in dry season (March). Correlation analysis showed that the structure and diversity of nirS-denitrifying microbial community had a close association with N pool (i.e., total nitrogen, NH₄⁺, and NO₃^-), C availability (i.e., microbial biomass carbon, easily oxidized carbon), and microclimate (i.e., soil water and temperature) during tropical forest restoration. Principal component analysis (PCA) showed that nitrate nitrogen, microbial biomass carbon, total nitrogen, and easily oxidized carbon were the key factors controlling community structure and diversity of nirS-denitrifying microbial community across three recovery stages of tropical forests. The effect of soil water content, temperature, hydrolytic nitrogen, pH, ammonium nitrogen, organic carbon, bulk density and C/N was ranked the next.