Objective To investigate the antiviral effect of antisense phosphorothioate oligodeoxynucleotides （ASODNs） complementary to three regions of HBV X gene （1510-1530, 1555-1581, 1768-1791）. Methods Three ASODNs and a sense strand （SODN） were synthesized. The inhibitory effect of the ASODNs on the expression of HBsAg, HBeAg, HBsAg and the ammount of HBV DNA was determined by ELISA, PAP-ELISA and in situ hybridization using 2. 2.15 cells. Results These ASODNs could inhibit the expression of HBxAg as well as HBsAg and HBeAg with the inhibitary rates of 78.07％, 80.65％ and 62.67％, respectively. And HBV DNA replication could be inhibited. The degree of the decrease in viral production and the amount of HBV DNA was dose- and timedependent. Conclusion The ASODNs directed against the three key regions of HBV X gene may block the expression of HBV antigens and the viral replication. The ASODNs may be a useful and potential antiviral agent for the treatment of HBV infection