Severe acute pancreatitis (SAP) is a serious acute inflammatory disease with complex pathogenesis, rapid progression, high mortality, extensive treatment, and heavy socioeconomic burden, which is often complicated by systemic multiple organ dysfunction. Renal replacement therapy (RRT) is essential for removing inflammatory mediators, cytokines or other toxins, as well as stabilizing the internal environment. Therefore, RRT is utilized as an organ support technology in the clinical management of SAP. Currently, there is no consensus regarding when and under what circumstances RRT can be employed in patients with SAP. In this paper, the pathogenesis of SAP and the indications and timing of initiation of RRT will be discussed.