Background: Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute deterioration in the setting of chronic liver disease associated with high short-term mortality. Currently, there is no specific treatment for patients with ACLF. Our previous results showed that Chinese herbal medicine (CHM) could reduce the mortality rate and the incidence of complications of ACLF effectively. In this study, we aim to conduct the multi-center randomized controlled trial to evaluate the effect of unified CHM formulas and provide propagable and high-level evidence for clinical practice. Methods/design: This is a prospective, multicenter, centrally randomized controlled trial. Five hundred and ten patients diagnosed with HBV-related ACLF will be allocated in a 1:1 ratio to SMT group (standard medical therapy) and CHM group (CHM and SMT). The primary outcome is the transplant-free mortality rates at week 4, 8, 12, 24 and 48. Secondary outcomes include (1) the incidence of adverse reactions, (2) influence on liver function, (3) the incidence of serious complications and (4) the level of inflammatory cytokines. Discussion: The effectiveness and safety of CHM formulas are assessed in the treatment of ACLF.