Objective To investigate the clinical effect of entecavir( ETV) combined with thymosin in the treatment of HBe Ag- positive chronic hepatitis B( CHB) patients. Methods A total of 108 HBe Ag- positive CHB patients who were treated in Department of Infectious Diseases in our hospital from March 2012 to March 2015 were enrolled,and according to the parallel,single- blind,randomized controlled principles,the patients were divided into control group( 54 patients) and observation group( 54 patients). The patients in both groups were given comprehensive medical treatment; the patients in the control group were treated with ETV alone,and those in the observation group were treated with ETV combined with thymosin. The changes in liver function parameters,virological parameters,immune indices,and liver fibrosis indicators were compared between the two group. The t- test was used for comparison of continuous data between groups,and the chi- square test was used for comparison of categorical data between groups. Results After 48 weeks of treatment,there were significant differences between the observation group and the control group in the liver function parameters albumin / globulin ratio( 1. 73 ± 0. 57 vs 1. 50 ± 0. 51,t =2. 210,P < 0. 05),alanine aminotransferase( 42. 58 ± 14. 32 U / L vs 54. 26 ± 18. 78 U / L,t = 3. 634,P < 0. 05),aspartate aminotransferase( 35. 79 ± 10. 33 U / L vs 49. 97 ± 17. 84 U / L,t = 5. 055,P < 0. 05),and total bilirubin( 18. 89 ± 6. 02 μmol / L vs 25. 24 ± 9. 06μmol /L,t = 4. 290,P < 0. 05). After 48 weeks of treatment,there were significant differences between the observation group and the control group in the liver fibrosis indicators laminin( 65. 34 ± 11. 02 ng / ml vs 102. 57 ± 16. 41 ng / ml,t = 13. 840,P < 0. 001),hyaluronic acid( 91. 68 ± 11. 53 ng / ml vs 151. 23 ± 16. 71 ng / ml,t = 21. 555,P < 0. 001),type IV collagen( 81. 02 ± 12. 64 μg / ml vs 118. 47 ±18. 01 μg / ml,t = 12. 507,P < 0. 001),and procollagen III( 70. 44 ± 13. 06 μg / ml vs 91. 57 ± 17. 16 μg / ml,t = 7. 200,P < 0. 001). At weeks 12,24,and 48 of treatment,the observation group had significantly higher HBe Ag clearance rates than the control group( 29. 63% /46. 30% /57. 41% vs 12. 96% /22. 22% /25. 93%,χ2= 4. 475,6. 948,and 11. 009,all P < 0. 05). After 48 weeks of treatment,compared with the control group,the observation group had a significantly lower serum level of interleukin- 4( 2. 69 ± 1. 23 pg / ml vs 4. 38 ±1. 44 pg / ml,t = 6. 558,P < 0. 001) and a significantly higher level of interferonγ( 1. 82 ± 0. 89 pg / ml vs 1. 12 ± 0. 56 pg / ml,t = 4. 812,P < 0. 001). There was no significant difference in the incidence rate of adverse events between the observation group and the control group( 3. 70% vs 1. 85%,χ2= 0. 343,P = 0. 558). Conclusion In HBeA g- positive CHB patients,ETV combined with thymosin can promote the recovery of liver function,regulate immune function,improve HBeA g clearance rate,and inhibit the process of liver fibrosis.