Abstract: Objective To study the expression and clinical significance of erythrocyte CR1 in patients with HBV-ACLF (HBV-acute-on-chronic liver failure). Methods A total of 31 HBV-ACLF patients and 15 healthy controls (HC) were enrolled in this study. Venous blood was extracted from 31 patients with HBV-ACLF and 15 healthy people. Flowcytometry was used to detect the expression of CR1 in patients with HBV infected liver diseases. RBC-C3bRR (RCR) was used for detection of CR1 immunity function. One tumor cell rounded by at least fve red cells was used as a rosette to calculate the ratios. HBV-ACLF patients were followed up for 8 weeks, and then they were divided into improved group and ineffective group according to the clinical effcacy. The changes of ECR1 in peripheral blood in improved group and ineffective group were observed dynamically. Results Our study showed that the expression of ECR1 was signifcantly higher in the control group than in the HBV-ACLF group (62.30±13.22) vs (41.21±14.33), t=3.33, P=0.021, and the ECR1 expression and adhesion activity in patients with HBV-ACLF was higher in improved group after 8 weeks than in ineffective group (47.31±16.36) vs (38.99±10.52), t=1.95, P=0.049, while there was no significant difference in adhesion activity between two groups. From dynamic view, expression and adhesion activity of ECR1 showed an increase in improved group, while a decline in ineffective group. Conclusion Expression and adhesion activity of ECR1 are correlated with the prognosis of HBV-ACLF. Patients with increased expression and adhesion activity of ECR1 have a better prognosis. Observation of ECR1 in patients with HBV-ACLF is of great clinical signifcance.