Biological treatment of domestic sewage low C/N ratio was accomplished in a pilot-scale sequencing batch biofilm filter (SBBF). The novel hybrid bioreactor consisted of bio-band in the upper and anthracite filter media in the bottom, which combined a sequencing batch biofilm reactor (SBBR) with a biological filter. The average removal efficiency values of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) were 89.4, 83.3, 62.9, and 48.7 %, respectively. A 454-pyrosequencing technology was employed to investigate the microbial communities of the influent (J1) and the biofilm(J2) on the bio-band on day 40. Pyrosequencing analysis of the 16S rRNA gene revealed the community of the biofilm consisted of Gammaproteobacteria (48.6 %), Planctomycetacia (18.0 %), Alphaproteobacteria (13.7 %), Clostridia (9.6 %), Desulfonatronum (18.5 %), Actinobacteria (1.9 %), and Bacilli (1.7 %), accounting for 93.6 % of total operational taxonomic units at genera level. Acinetobacter tjernbergiae and Acinetobacter lwoffii were the most abundant species, suggesting that denitrifying phosphorus removal was achieved in the SBBF.