The invention relates to a preparation method of an organic/inorganic nano-assorted fiber. The preparation method comprises the procedures that (1) inorganic substance suspends in dimethyl acetamide or formic acid spinning solvent in the water bath with the temperature of 20 to 60 DEG C; macromoleclar polymer is added and stirred at the rotating speed of 200 to 450rpm and swells for 24 hours in the water bath with the temperature 20 to 60 DEG C; and the macromoleclar polymer is cooled to room temperature to acquire dope with even dispersion: and (2) the dope is poured into a liquid reservoir; a bullet-shaped syringe needle is adopted as a capillary for spraying a streamlet; after HYEF spinning, the dope is dried under vacuum and normal temperature; and optional post-treatment is carried out, the functional composite nano fiber is made. The preparation method is simple with mild preparation condition and simplifies compound process. The composite nano fiber has high superficial area and is widely dispersed, so the composite nano fiber is applicable for preparing a drug delivery system, anti-bacterial textile, material separation, the water pollution treatment of metal ions and organic compound, etc.