The invention belongs to the technical field of electrochemistry, and particularly relates to a carbon-coated alloy nanoparticle electrode material for lithium ion batteries and a preparation method. The electrode material body is a nano-alloy material. Phenolic resin is uniformly coated with alloy nanoparticles through emulsion polymerization to form a core-shell structure, and finally, carbon-coated alloy nanoparticles are obtained by high temperature calcination and carbonization in an inert atmosphere. In the structure of this composite material, nano-alloy particles are uniformly and firmly wrapped by carbon with good conductivity and certain expansion and contraction properties, so volume expansion can be buffered during the cycle and the electrical conductivity of the overall electrode is ensured.

By using this composite material as a lithium ion battery anode material, a lithium ion battery anode material with high lithium storage capacity, excellent safety and excellent cycle performance can be obtained