Abstract: Objective To observe the variation of Th17/Treg balance in different ALT levels of chronic hepatitis B and effect of entecavir. Methods Eighty-five CHB patients in Hangzhou Red Cross hospital during June, 2012 to October, 2012 were divided into three groups; mildly, moderately, significantly elevated ALT and 30 healthy volunteers were enrolled as healthy controls. The peripheral blood Th17, Treg of 30 patients from the above cases were measured after entecavir antiviral treatment for 24 weeks. Results Th17 cell levels, Treg cell levels and Th17/Treg ratio of CHB patients were significantly different than those of healthy volunteers (P<0.05). The difference in Th17/Treg ratio between 3 groups of CHB patients with different ALT levels was statistically significant (P<0.05). Th17 was positively correlated with ALT, and Treg was negatively correlated with ALT. At 24 weeks after entecavir antiviral treatment, the differences of ALT level, HBV-DNA load and Th17/Treg were statistically significant (P<0.05). The ratio of Th17/Treg in patients with Normal ALT and HBV-DNA (22 cases), ALT and/or HBV-DNA abnormality (8 cases) was significantly lower than that of baseline (P<0.05). There was no statistical difference in the comparison of the baseline Th17/Treg ratio and the comparison of the two groups after the treatment (P>0.05). Conclusion Th17/Treg was unbalanced in CHB patients and correlated with the ALT levels. Entecavir treatments was beneficial to the balance of Th17/Treg.