The invention discloses a lithium-ion battery and a coating method of an electrode active material of the lithium-ion battery, and relates to chemical grafting of an organic layer to the surface of an electrode material. The method comprises: carbonizing the organic layer to form a doped carbon layer on the surface of the electrode material in a chemical bonding manner; and reacting a doped substance in the doped carbon layer with a hazardous substance formed in a charging and discharging process of the lithium-ion battery to protect the electrode material, wherein the doped substance in the doped carbon layer can improve the electrical conductivity of the doped carbon layer. The invention further provides the lithium-ion battery, the electrode material of which comprises the carbon layer doped in a chemical bonding layer. The doped substance can react with the hazardous substance resulting from electrolyte decomposition in the charging and discharging process of the lithium-ion battery. The doped substance contained in the doped carbon layer can improve the transmission rate of electrons, so that the electrical conductivity of the electrode material and an electrode prepared from the electrode material is improved.