The invention discloses a preparation method of a zinc ferrite nano-material and belongs to the technical field of nano-material preparation. The ZnFe2O4 nano-material is prepared in the way that a solvothermal method is adopted to prepare a metal-organic precursor material, and then a high-temperature calcining method is adopted for treatment. The zinc ferrite nano-material is prepared by the following steps: zinc nitrate hexahydrate, ferric acetylacetonate, terephthalic acid and polyvinylpyrrolidone are dissolved in a N,N-dimethylacetamide and ethyl alcohol mixed solution; stirring is performed at the room temperature, an obtained turbid liquid is transferred into a reaction kettle, heating is performed under a certain temperature condition, and centrifugal separation and vacuum drying are performed to obtain a precursor Fe III-MOF-5 nano-material; and high-temperature calcination is performed at a certain temperature to obtain the ZnFe2O4 nano-material. The preparation method is simple, green, pollution-free and high in degree of practicability, and the prepared ZnFe2O4 nano-material can directly serve as a gas-sensitive material for use.