Abstract： Functional cure of chronic hepatitis B ( CHB) through antiviral therapy is the goal and main focus of research worldwide.The criteria of functional cure of CHB are undetectable serum HBV DNA, persistent loss of HBsAg, with or without anti-HBs seroconversion, persistence of cccDNA in a transcriptionally inactive status and the absence of spontaneous relapse after treatment cessation .Current antiviral therapy can effectively control viral replication , but is still quite far from achieving functional cure. From the virological point of view , HBV cccDNA reservoir and its transcription activity can hardly be inhibited by the existing antiviral therapy , and the integration of viral genomic DNA leads to the continuous expression of HBsAg, which are the two main causes of the low functional cure rate in CHB patients. Furthermore, the high frequency of viral mutation can also result in a reduction of HBsAg loss .This article reviews the new strategies and advances about functional cure of CHB based on the virology research .