In order to reduce the energy consumption of sewage treatment, this study uses zeolite particles as biological fillers to build a fixed-bed biofilm reactor, and the biofilm on the filler surface in the reactor is placed in an alternating anaerobic-aerobic environment through the sequential batch water-drainage method. It avoids the large amount of energy consumption required by the traditional sewage treatment aeration process, and effectively removes COD and denitrification at the same time. The main principle of the process is that in the anaerobic stage (influent), the sewage is in contact with the biofilm and zeolite particles, and the glycan bacteria (GAOs) convert the organic carbon source into intracellular polyhydroxyalkanoates (PHAs), and the zeolite absorbs NH₄⁺-N in the sewage. In the aerobic stage (drainage), the combined action of glycan bacteria, nitrifying bacteria and denitrifying bacteria converts the NH₄⁺-N adsorbed by the zeolite into nitrogen, so that the biofilm and zeolite particles can be regenerated. The zeolite particle fixed-bed biofilm reactor uses activated sludge as the inoculation sludge. Under the sequential batch anaerobic-aerobic alternate operation mode, it successfully started within 2 weeks; in the long-term operation, removal of COD, NH₄⁺-N and TN rate in sewage was 87%, 83% and 83%, respectively, and no nitrate nitrogen was detected in the effluent; after long-term operation, the biofilm flora in the reactor was dominated by Thaurea, Candidatus competitivebacter , and Nitrospira. They are the key microorganisms for COD removal and denitrification.