Abstract: Objective To investigate the impact of the timing of continuous renal replacement therapy (CRRT) on the efficacy and prognosis of patients with septic shock undergoing bundle therapy. Methods A total of 84 patients with septic shock who underwent bundle therapy were enrolled, receiving bundle therapy. Based on the timing of CRRT, the patients were divided into early CRRT group and late CRRT group, with 42 patients in each group. Clinical data (heart rate, time to normalization of body temperature, ICU length of stay) and infection statusC-reactive protein (CRP), procalcitonin (PCT)and immune function (CD4⁺, CD8⁺, CD14⁺), as well as the Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) scores before and after treatment were compared between the two groups. The 28-day survival of patients in both groups was also followed up. Results The heart rate in the early CRRT group was lower than that in the late CRRT group, and the time to normalization of body temperature and ICU length of stay were shorter in the early CRRT group compared with the late CRRT group (P<0.05). After treatment, the levels of CRP and PCT in both groups were lower than those before treatment, and their levels in the early CRRT group were lower than those in the late CRRT group (P<0.05). After treatment, the levels of CD8⁺ in both groups were lower than those before treatment, and the early CRRT group had lower level than that in the late CRRT group (P<0.05); after treatment, the levels of CD4⁺ and CD14⁺ in both groups were higher than those before treatment, and their levels in the early CRRT group were higher than those in the late CRRT group (P<0.05). After treatment, the APACHE Ⅱ scores of both groups were lower than those before treatment, and the early CRRT group had lower APACHE Ⅱ score than that in the late CRRT group (P<0.05). The follow-up results showed that the 28-day cumulative survival rate was 83.33%(35/42) in the early CRRT group, which was higher than 64.29%(27/42) in the late CRRT group (P<0.05). Conclusion For patients with septic shock undergoing bundle therapy, early application of CRRT is superior to late application in clinical efficacy, and contributes to improving the prognosis of patients.