The invention relates to a copper-graphene composite material with an interface improved by rare earth elements. Copper powder is adopted as a base material of the copper-graphene composite material,the adopted graphene is grown in situ on the copper surface through a carbon source, the rare earth elements are added to the interface between copper and graphene for modification, and the bonding strength of the modified interface can be improved by 10%-30% on the premise that the original elongation is guaranteed. The invention also provides a preparation method of the copper-graphene compositematerial.