In addition to immune regulation, interferon could suppress hepatitis B virus (HBV) replication through direct antiviral effect. After binding with the receptors on cell membrane, interferon directly inhibits HBV at different steps in HBV replication cycle by activating cell signaling cascades such as JAK-STAT pathway, interferon regulatory factor (IRFs) signaling pathway, and so on, followed by inducing a series of cytokines which are involved in regulation of the function of HBV enhancer I / X promoter (Ehn I / Xp). Also, interferon could induce the host cells to produce anti-viral proteins. This review describes the direct antiviral mechanism of interferon on HBV.