Chronic hepatitis B (CHB) is a serious liver disease worldwide, and the leading cause of cirrhosis and hepatocellular carcinoma (HCC). HBsAg loss/seroconversion is considered to be the ideal endpoint of antiviral therapy in both HBeAg-positive and -negative patients, and the ultimate treatment goal in CHB, However HBsAg loss occurred rarely by interferon treatment. Although It was reported that in nature history HBsAg level≤100 IU/ml can bring good long term outcomes in patients with chronic hepatitis B. it was not clear whether patients who achieved HBsAg level≤100 IU/ml by interferon treatment could maintain sustained viral response and the state of HBsAg level≤100 IU/ml.