Metallic lithium is regarded as one of the most promising electrode materials to break through the energy density bottleneck of current commercial lithium-ion batteries. However, the practical implementation of lithium metal anode is limited by the unstable electrode interface significantly, which directly induces a low Coulombic efficiency, short cycling lifespan, and dendritic lithium growth behavior. In this study, via in situ electropolymerization, lithiophilic and conformal polyaniline layer is developed to improve the initial lithium nucleation and plating process, reducing the interface charge transfer resistance and promoting uniform lithium plating/stripping behavior. Meanwhile, the polyaniline layer exhibits good adhesion to the substrate. As a result, the Li/Cu half cell delivers a high Coulombic efficiency of 99.1% for 400 cycles at 1.0 mA·cm⁻² with polyaniline layer. In addition, long-term stable cycling at a current density of 1.0 mA·cm⁻² for 1300 h has been achieved for lithium metal anode. This strategy provides a new perspective for the practical lithium metal batteries.