NOVELTY - A niobium-doped lithium-cobalt-aluminum composite positive material preparing method involves dissolving lithium acetate, cobalt chloride, niobium nitrate and aluminum sulfate in deionized water to obtain solid content, adding the solid content with polybutene acid to obtain to obtain xerogel powder, sintering to obtain niobium-doped lithium-cobalt-aluminate material, preparing uniform solution, dispersing the solution with graphene powder to obtain graphene polymer material, coating the polymer material on niobium-doped material, followed by heating and cooling to obtain finished product.    USE - Method for preparing niobium-doped lithium-cobalt-aluminum composite positive material that is utilized for lithium ion battery.    ADVANTAGE - The method enables preparing niobium-doped lithium-cobalt-aluminum composite positive material with high capacity, electrochemical circulation stability and machine stability, and long use life.    DETAILED DESCRIPTION - A niobium-doped lithium-cobalt-aluminum composite positive material preparing method involves dissolving lithium acetate, cobalt chloride, niobium nitrate and aluminum sulfate in deionized water to obtain solid content, adding the solid content with 45-50 wt.% polybutene acid complexing agent in a water bath at 50-60 degrees C for 3-5 hour to obtain a sol, evaporating the sol to obtain wet gel, drying the wet gem at 120-125 degrees C for 4-6 hours to obtain xerogel powder, sintering the powder at 700-900 degrees C to speed of 10-15 rpm for 3-5 hours and cooling to obtain niobium-doped lithium-cobalt-aluminate material, stirring 0.15-0.2 mol/l disodium hydrogenphosphate, 0.01-0.015 mol/l ferric chloride, 0.01-0.015 mol/l disodium hydrogen phosphate, electrolyte lithium perchlorate and0.2-0.4 mol/l thiophene monomers to form uniform solution, dispersing the solution with graphene powder, and washing with water after drying to obtain graphene polymer material, coating the graphene polymer material on niobium-doped lithium-cobalt-aluminate material, followed by heating at 750-800 degrees C to speed of 5-10 rpm for 4-6 hours and cooling to obtain finished product.