Abstract: To reflect the nitrification performance in the pulse trickling filter，this paper built a biofilm reaction model based on the biological membrane diffusion model，which was based on the mass balance equation，the first Fick law，and the simplified ASM3 model． MATLAB was used to simulate the concentration along the pulse tricking filter，and the parameters were corrected by the measured values and sensitivity of values． The actual measurement data and the simulation result both indicated that the removal of COD，NH + 4 －N，NO － 2 －N，NO － 3 －N mainly concentrated in the middle-upper，middle，lower part and the removal rates of COD and ammonia nitrogen were 45% and 50% respectively． When the organic load and water cycle changed，the ammonia removal rate decreased with the organic load increasing and went up with the increasing of water cycle．