An anti-aging method of a cable comprises the step of coating the outer surface of an insulating material of the cable with nanometer coating so as to form a coating. The nanometer coating comprises the following components in parts by weight: 30-50 parts of a modified polysiloxane emulsion, 50-100 parts of a solvent, 1-10 parts of an emulsifier, 5-10 parts of methyl siloxane and 0.1-0.5 part of atitanium-containing catalyst. The anti-aging method is characterized in that a nanometer dispersion comprises inorganic nanoparticles and an organic solvent, and on the basis of siloxane repairing, through filling of the inorganic nanoparticles, the remaining life of a power cable is further prolonged by 5-100 times.