The invention provides preparation and application of a metal vanadium efficient adsorption-reduction material taking waste green tea residues as a raw material. The green tea residues are composed of 17%-28% of crude protein, 16%-35% of crude fiber, 2%-3% of free amino acid, 1%-2% of tea polyphenol, 0.1%-0.3% of caffeine and the like. After the green tea residues are pyrolyzed into biochar, the variety and number of functional groups of unsaturated bonds on the surface are large, and the original vanadium adsorption capacity is obviously superior to that of other biochar. Zero-valent iron modification is carried out on the surface and pore channels of the green tea residue biochar, the pore channel structure of the biochar is optimized, the reducing capacity of the biochar is enhanced, the vanadium adsorption capacity is improved, and efficient adsorption-reduction of vanadium is achieved. After modification, the adsorption capacity is improved by 3.48-11.28 times, the adsorption rate is improved by 20-36 times, pentavalent vanadium is reduced into tetravalent vanadium with low toxicity, and the toxicity is reduced by 70% or above. The material is simple and convenient in synthesis method and excellent in repairing effect, can be applied to scenes such as a permeable reactive barrier technology or vanadium pollution emergency treatment, remarkably reduces the early-stage investment and operation cost of a project, and has a good practical application prospect.