The rapid start-up of nitrification biological aeration filter (BAF) at low temperature was explored by using artificial water distribution to improve the efficiency of the biological nitrogen removal of wastewater treatment facilities in winter of northern China. The results showed that the influent concentrations of NH+4—N and COD were 103.16 mg/L and 60 mg/L, respectively, under the condition of 10~16℃, and the inoculation biofilm method combined with natural biofilm method was adopted. The results showed that the effluent concentrations of NH+4—N and COD decreased to 36.17 mg/L and 6.66 mg/L, respectively, and the removal rates were 62.74% and 87.30%, the concentration of NO-3—N reached to 60.23 mg/L when the system ran to the 25th day. The nitrifying performance was well in nitrification BAF. The light brown sticky film became thickened fulvous biofilm on the surface of filler when the nitrification BAF was started up successfully.