Chronic hepatitis B（CHB）is one of the major challenges in the global public health field. As of 2022，approximately 254 million people worldwide were infected with the hepatitis B virus（HBV）. CHB is one of the main causes of liver cirrhosis and hepatocellular carcinoma（HCC）. Nucleos（t）ide analogs（NAs）and interferon therapy can delay the progression of liver fibrosis by inhibiting viral replication，but they cannot completely avoid the problem of heterogeneous treatment responses. Some patients are in a state of low-level viremia（LLV）during treatment. The persistent LLV state can induce chronic inflammation and the progression of liver fibrosis，ultimately increase the risk of HCC. In patients with poor treatment responses，the continuous active viral replication can induce immune disorders，accelerate the evolution of fibrosis to the decompensated stage of liver cirrhosis，and increase the risk of patient death. This article aims to review the definition，mechanisms，and impact on treatment outcomes of LLV and suboptimal response based on the latest research，provide a basis for optimizing antiviral therapy for CHB.

Chronic hepatitis B（CHB）is one of the major challenges in the global public health field. As of 2022，approximately 254 million people worldwide were infected with the hepatitis B virus（HBV）. CHB is one of the main causes of liver cirrhosis and hepatocellular carcinoma（HCC）. Nucleos（t）ide analogs（NAs）and interferon therapy can delay the progression of liver fibrosis by inhibiting viral replication，but they cannot completely avoid the problem of heterogeneous treatment responses. Some patients are in a state of low-level viremia（LLV）during treatment. The persistent LLV state can induce chronic inflammation and the progression of liver fibrosis，ultimately increase the risk of HCC. In patients with poor treatment responses，the continuous active viral replication can induce immune disorders，accelerate the evolution of fibrosis to the decompensated stage of liver cirrhosis，and increase the risk of patient death. This article aims to review the definition，mechanisms，and impact on treatment outcomes of LLV and suboptimal response based on the latest research，provide a basis for optimizing antiviral therapy for CHB.