Abstract： Objective:To explore the efficacy evaluation of continuous renal replacement therapy(CRRT) in elderly patients with severe pneumonia complicated with systemic inflammatory response syndrome.Methods:This study was a randomized controlled study, a total of 90 elderly patients with severe pneumonia complicated with systemic inflammatory response syndrome admitted to the department of Cadre Wards and Critical Care Medicine in General Hospital of Northern Theater Command from January 2013 to January 2024.There were 61 males and 29 females, aged(68 ± 7) years old, ranging from 61 to 75 years old.The patients were randomly divided into conventional treatment group and CRRT group using a random number table method, with 45 cases in each group.The conventional treatment group received conventional treatment, while the CRRT group received CRRT in addition to the conventional treatment group.Time for respiratory rate to return to normal, time for body temperature to return to normal, length of hospital stay, levels of inflammatory factors[interleukin-6, C-reactive protein(CRP), procalcitonin], effective rate, and incidence of complications were compared between the two groups of patients.Results:The time for respiratory rate to return to normal[(10.62 ± 2.92) h], body temperature to normal[(20.09 ± 6.35) h], and hospital stay[(7.12 ± 2.02) d]in CRRT group were all shorter than those in conventional treatment group[(19.58 ± 5.44) h, (47.59 ± 13.42) h, (12.85 ± 5.59) d].After 3 d of treatment, the levels of interleukin-6[(11.94 ± 2.46) ng/L], CRP[(0.84 ± 0.58) ng/L], procalcitonin[(188.27 ± 28.02) ng/L]in CRRT group were lower than those in conventional treatment group[(15.39 ± 3.15) ng/L, (1.42 ± 0.17) ng/L, (249.95 ± 35.72) ng/L]; the effective rate of patients in CRRT group[86.7%(39/45)]was higher than that in conventional treatment group[66.7%(30/45)]; the incidence of complications in CRRT group[4.4%(2/45)]was lower than that in conventional treatment group[28.9%(13/45)], and the differences were statistically significant( P<0.05). Conclusions:Severe pneumonia in elderly patients with CRRT combined with systemic inflammatory response syndrome has a shorter disappearance time of respiratory distress and hospital stay, lower levels of inflammatory factors, better treatment effect, and lower incidence of complications.