Abstract：The high concentration of ammonia nitrogen is one of the important reasons why it is difficult to control black-odorous water. This study compared the filming characteristics of strains domesticated with activated sludge and commercial nitrifying bacteria inoculation on polypropylene fiber and zeolite, and investigated the effects of different film carrier properties, filler particle size and pH on the removal of ammonia nitrogen. The comprehensive mechanism of ammonia nitrogen removal by biofilm method with filler loading bacteria was explored by deconstructing the differences of microbial communities in different fillers biofilms through high-throughput sequencing. The results showed that when activated sludge was used as the source of microorganisms, the biomass after biofilm formation reached 0.36g·g-1 DW and the biological activity reached 8 mg· (g· h)-1, which were significantly higher than those of the commercial nitrobacteria liquid. The removal efficiency of ammonia nitrogen in simulated wastewater can reach up to 84.23% at 108 h when the dosage of the polypropylene fiber carrier was 12 g·L-1 and the pH value was 8, and the significant abundance difference of Paenarthrobacter is the main reason that the removal effect of ammonia nitrogen from bacteria-loaded polypropylene fibers is better than that of bacteria-loaded zeolites with particle size of 1 mm. During ammonia nitrogen removal, the biological degradation was up to 90.75%, while only 9.25% was removed in a physical adsorption. Biological degradation is the main degradation way of ammonia nitrogen.