This study was conducted using Chlorella pyrenoidosa based on previous screening and domestication. The Chlorella was inoculated into sewage mixed with the effluent from the primary sedimentation tank and sludge digestion liquid in different proportions (1 ∶ 0, 3 ∶ 1, 1 ∶ 1, 1 ∶ 3, and 0 ∶ 1), observing the growth rate and oil yield of Chlorella pyrenoidosa, as well as the pollutant removal rate inthe sewage. The results in dicated that the highest algal concentration of 0.704 g / L was achieved when Chlorella was cultured in sewage with a ratio of 3 ∶ 1. Furthermore, the best oil production effect and maximum oil production rate of 36.29% were observed when Chlorella was cultured in sewage with a ratio of 1 ∶ 1. Chlorella demonstrated effective removal of NH+4 -N, TN, and PO3-4 -P in sewage across all ratios, but had a poor removal effect on COD. Additionally, the concentration of NO3 -N remained consistently low throughout the culture process. Chlorella exhibited better removal of TP in sewage with ratios of 1 ∶ 0, 3 ∶ 1, and 1 ∶ 1, while the ratios of 1 ∶ 3 and 0 ∶ 1 showed less effective removal. Overall, the most favorable Chlorella culture was achieved in sewage with a ratio of 3 ∶ 1.