Abstract: The effluent from municipal wastewater treatment plants contains nitrogen and phosphorus compounds, and the effluent discharged into the water body is still easy to cause eutrophication. The study on advanced treatment of effluent to further remove nitrogen and phosphorus pollutants is of practical significance. The removal effect of co-cultivation of different bacteria and microalgae on nitrogen and phosphorus was studied in the experiment, and the combination of dominant bacteria and microalgae was screened out. Response surface methodology (RSM) was used to study the interactive effects of light wavelength (LW), aeration rate (AR) and the inoculation ratio of bacteria (IR) on the removal effect of nitrogen and phosphorus. The optimal parameter combination was proposed, a microalga-bacterial symbiosis system was established, and a verification experiment was carried out. The results showed that among different combinations of algae and bacteria, the co-culture group of Chlorella proteinosa, Bacillus licheniformis and Pseudomonas putida had the best removal effect on TN and TP. When LW was blue light, AR was 1.8 L/min, and IR was 20%, TN maximum removal rate could reach 93.7%, and TP was basically completely removed after 1 day. When LW was blue light, AR was 2.0 L/min, and IR was 5%, the removal rate of ammonia nitrogen after 2 days was 98.4%. When LW was red light, AR was 2.0-3.0 L/min, and IR was 10%-20%, ammonia nitrogen after 2 days was basically completely removed. When LW was blue light, AR was 1.8 L/min, and IR was 20%, it was the optimal parameter condition for nitrogen and phosphorus removal efficiency. The verification results of the optimized parameter combination were consistent with the predicted values. The effluent of the system met Class Ⅴ of Environmental Quality Standards for Surface Water (GB 3838-2002), which provided a theoretical basis for the practical application of the microalgae-bacteria symbiotic system.