To verify the feasibility of biofilm-membrane bioreactor in municipal wastewater treatment. In this paper, based on the Fourier series algorithm, the basic configuration of biofilm-membrane bioreactor, the design of membrane bioreactor test index and method, the proposed urban wastewater treatment system based on biofilm-membrane bioreactor, and the creation of experiments to verify the biofilm-membrane bioreactor with the example of urban wastewater in the sewer of residential buildings in the district on the two CODCr and NH4+-N in urban wastewater in municipal wastewater. The results showed that the removal rate of CODCr in municipal wastewater by the biofilm-membrane bioreactor system increased with time, and the removal rate was stable at about 83%. The NH4+-N removal rate increased with time and was stable between 85 and 90%. It can be shown that biofilm-membrane bioreactor can sufficiently reduce the concentration of CODCr and NH4+-N in municipal wastewater, thus promoting municipal wastewater treatment. It also presents a new solution for urban wastewater treatment.