This study was conducted using Chlorella pyrenoidosa based on previous sereening and domestication. The Chlorella was inoculated into sewage mixed with the efluent 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 in the sewage. The results indicated that the highest algal coneentration 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 NH4+-N, TN , and PO43--P in sewage across alratios, but had a poor removal effect on COD. Additionally, the concentration of NO3--N remained consistently low throughout the culture process. Chlorella exhibited belter 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.