Various studies showed that entecavir (ETV) failed to improve the short-term survival in chronic hepatitis B (CHB) patients with severe acute exacerbation (SAE) and hepatic de-compensation or acute-on-chronic liver failure (ACLF). One study concluded that plasma exchange (PE) significantly decreased the short-term mortality of CHB patients with ACLF who were treated with lamivudine (LAM). Our study was designed to examine the effect of PE on CHB patients with ACLF who were treated with ETV. From August 2010 to January 2015, 38 (PE group) and 120 (control group) consecutive CHB-na < ve patients with hepatic de-compensation and ACLF treated with PE plus ETV and ETV, respectively, were recruited. The primary endpoint was liver-related mortality at week 12. Biochemical and virological responses were also studied. At baseline, the PE group had higher serum alanine aminotransferase (ALT) levels and model for end-stage liver disease (MELD) scores, and had lower albumin levels than the control group. The cumulative survival rate at week 4 and week 12 in the PE group and control group were, respectively, 37 and 18 %, and 29 and 14 % (p < 0.001, by log rank test). While the bilirubin levels in the PE group were more quickly lowered by PE therapy (p < 0.001), the decrease of ALT levels and virological response were similar in the two groups (p > 0.05). Univariate analysis showed that the control group had a higher liver-related mortality (p = 0.038) at week 12 than the PE group. Multivariate analysis showed that hepatic encephalopathy, ascites, PE treatment, and MELD scores were independent factors for liver-related mortality at week 12. PE significantly improved the short-term survival of CHB patients with hepatic de-compensation and ACLF who were treated with ETV. Hepatic encephalopathy, ascites, PE treatment, and MELD scores were independent factors for liver-related mortality at week 12.