[Objective] Periphyton, a kind of microbial aggregates, grows generally at the water-soil interface in paddy fields, and plays an important role in regulating nitrogen cycling in the paddy fields. This study was conducted to explore effects of perphyton on ammonia volatilization, and relationships of ammonia volatilization with microbial community structure of the periphyton and physico-chemical properties of the surface floodwater in the paddy field, so as to provide certain theoretical guidance and technical support for controlling ammonia emission in paddy fields. [Method] In this study, a field experiment was carried out with two treatments designed to be: 1) with normally growing periphyton, and 2) with terbutryn (C₁₀H₁₉N₅S) added to regulate growth of periphyton. Each treatment had three replicates. Ammonia volatilization was monitored after the application of base fertilizer (BF), tillering fertilizer (TF) and heading fertilizer (PF), separately, for analysis of changes in ammonia volatilization rate as affected by periphyton, calculation of ammonia flux volatilized throughout the entire rice growing season, and determination of relationships of ammonia volatilization with microbial community structure of the periphyton and physico-chemical properties of the surface floodwater, in an attempt to establish a model to predict ammonia volatilization from paddy fields based on periphyton growing in the field.[Result] Results show: 1) the cumulative loss of ammonia via volatilization reached 24.75±1.05 kg·hm^-2 and 10.92±0.07 kg·hm^-2 in the treatment with periphyton growing normally, after the application of base fertilizer (BF) and tillering fertilizer (TF), respectively, and was 71.3% and 39.3%, respectively, lower in the treatment with terbutryn added, however, it did not differ much between the two treatments at the panicle stage (); 2) Ochrophyta, Cryptomycota and Nematoda were the dominant eukaryotic microbes in the study area (accounting for 42.6%-67.6%) while Proteobacteria, Bacteroidetes, Chloroflexi (14.6%-0.8%), Acidobacteria were the dominant prokaryotic microbes (accounting for 52.1%-58.1%); and 3) Correlation analysis shows that biomass of the periphyton, nitrogen content in the floodwater and wind speed are the key factors affecting daily ammonia volatilization flux. [Conclusion] To sum up, the effect of addition of C₁₀H₁₉N₅S changing community structure of the periphyton can effectively reduce ammonia volatilization from paddy soil by modulating growth of the periphyton during the periods after the application of base and tillering fertilizers, and hence alleviate N loss via ammonia volatilization.