The invention discloses an environment coordination type preparation method of nano titanium dioxide powder, which comprises the steps of: by using green resource water as a single solvent, one of tetrabutyl titanate, titanium dioxide, titanyl sulfate, metatitanic acid, titanium sulfate and titanium tetrachloride as a titanium source, ammonia water or urea as a neutralizing agent, and ammonium nitrate as a combustion improver, introducing the ammonium nitrate by adopting the ammonia water and nitric acid or singly adding the ammonium nitrate, using lactic acid as a stabilizing agent, a chelating agent, a swelling agent and a pore-forming agent, preparing sol at room temperature by adopting a water-based sol-gel method, regulating the pH value by the sol, obtaining cream yellow opaque gel after the solvent is removed, spontaneously igniting, swelling and pore-forming the gel to obtain a nano pyrophorus, and thermally treating the pyrophorus for 0.5-1h at the temperature of 500-800 DEG C to prepare the nano titanium dioxide powder with different crystal phase structures. The prepared nano titanium dioxide powder has the advantages of no agglomeration, porous nano thin layer, uniform pore distribution, uniformity in pores and larger specific surface area.