〔Abstract〕 Objective To observe and study the clinical efficacy of plasma exchange on 29 patients with acute liver failure. Methods The clinical data of 29 patients with acute liver failure admitted to Xiangan Hospital of Xiamen University from December 2019 to December 2020 were retrospectively analyzed. All patients received comprehensive medical treatment and plasma exchange therapy. The changes of liver function, blood ammonia, serum osmotic pressure, electrolytes, lipopolysacchraride (LPS), serum tumor necrosis factor-α (TNF-α), serum interleukin-6 (IL-6), coagulation function and prothrombin activity (PTA) were observed before and after treatment, and the outcomes of patients were statistically analyzed. Results After treatment, all liver function indexes, blood ammonia level, serum osmotic pressure, Cl- level, LPS, TNF-α and IL-6 were lower than those before treatment, while the prothrombin time (PT), activated partial thrombin time (APTT), thrombin time (TT) and PTA were higher than those before treatment, the differences were statistically significant (P < 0.05). After treatment, the clinical improvement rate was 72.41 %, the 28-day survival rate was 55.17 %, and the 90-day survival rate was 27.59 %. Conclusion Plasma exchange in the treatment of acute liver failure is more helpful to improve liver function indexes, blood ammonia level, serum osmotic pressure,serum LPS, serum TNF-α, serum IL-6 level, coagulation function, PTA and prognosis of patients, but attention should be paid to the appropriate electrolyte supplement.