The invention relates to the technical field of inorganic materials, and discloses a preparation method for a ferrous carbonate/graphene composite material. The preparation method comprises the steps of: I. mixing graphene materials, water-soluble ferrite, urea and water to form a suspension, wherein the mass ratio of the graphene materials to the water-soluble ferrite is (0.02-0.2):1, and the amount-of-substance concentration ratio of the urea to the water-soluble ferrite is (20-100):1; II. putting the suspension into a reaction kettle, controlling the temperature to be 100-180DEG C, and carrying out hydrothermal reaction for 4-12h to obtain the ferrous carbonate/graphene composite material. The invention further provides a lithium ion battery prepared by taking the ferrous carbonate/graphene composite material as a negative electrode material. By being synthesized through low-temperature hydrothermal reaction, the ferrous carbonate/graphene composite material is high in specific capacity and good in cycling performance, and has excellent development prospects after being applied to the negative electrode materials of the lithium ion battery.