Abstract: Objective To analyze the effect of continuous blood purification (CBP) on inflammatory factors and immune function in elderly patients with acute renal failure (ARF) and systemic inflammatory response syndrome (SIRS), and to provide reference for improving the treatment of elderly patients with ARF and SIRS. Methods From March 2017 to June 2018, 78 elderly patients with ARF and SIRS were divided into 2 groups, experimental group, 40 cases were given CBP therapy, and control group, 38 cases were given routine treatment. Inflammatory factors, immune function before and after treatment, hospital mortality and average hospitalization days were evaluated. SPSS 20.0 statistical software was used to statistical analysis. Results On the third day after treatment, the levels of IL-6, IL-8 and TNF-α in the two groups were lower than those before treatment (P<0.05), and the experimental group were lower than those in the control group (P<0.05). On the third day after treatment, the ratio of CD4⁺ and CD4⁺/CD8⁺ increased (P<0.05) and CD8⁺ decreased (P<0.05) in the experimental group, and the ratio of CD4⁺and CD4⁺/CD8⁺ in the experimental group was higher than that in the control group (P<0.05), while the ratio of CD8⁺ was lower than that in the control group (P<0.05). The mortality rate in the control group was higher than that in the experimental group (P<0.05), but there was no significant difference in the average length of stay between the two groups (P>0.05). Conclusion On the basis of routine treatment, CBP has a positive effect on reducing inflammatory factors, improving immune function in elderly patients with ARF and SIRS.