A series of caudatin derivatives were synthesized, and their anti-hepatitisBvirus (HBV) activity was evaluated in HepG 2.2.15 cells. Most of the 3-O-substituted caudatin derivatives showed effective anti-HBV activity. Among the tested compounds, six compounds (2e–2h, 2l, 2r) exhibited significantly inhibitory activity against HBV DNA replication with IC50 values in the range of 2.82–7.48 μM. Interestingly