The invention discloses an EVA (Ethylene Vinyl Acetate) foamed material with a thermoplastic blue-green algae biomass and a preparation method thereof. The EVA foamed material comprises the following main components in parts by weight: 15-50 parts of a thermoplastic blue-green algae biomass, 50-85 parts of EVA, 0.5-2.5 parts of a cross-linking agent, 1-5 parts of a lubricant and 1-4 parts of a foaming agent, wherein the thermoplastic blue-green algae biomass is prepared from the following components in parts by weight: 100 parts of blue-green algae biomasses, 50-100 parts of a reaction solvent, 0.5-5 parts of a catalyst, 5-20 parts of a modifier, 50-100 parts of a grafting monomer and 1-10 parts of an initiator. The preparation method comprises the following steps: synthesizing the thermoplastic blue-green algae biomass through polymerization reaction, putting the thermoplastic blue-green algae biomass, the EVA, the cross-linking agent, the lubricant and the foaming agent into a high-speed stirrer, sufficiently stirring for 10-30 minutes at 60-100 DEG C, mixing and melting the mixture for 10-20 minutes at 100-120 DEG C, after complete melting and plastification, discharging a flaky material, cutting, cross-linking, and foaming, thereby obtaining the foamed material. A feasible way for high-end application of blue-green algae resources is provided.