The invention discloses a preparation method of cefoxitin sodium superfine-powder preparations. The method comprises the following steps: 1, at room temperature, adding 7-alpha-methoxy-3-deacetyl cefalotin benzathine to acetone; 2, pouring reaction liquid obtained after reaction into ionized water, stirring the obtained mixture to carry out a hydrolysis reaction at 0-25 DEG C; 3, adding ethyl acetate to the obtained hydrolysis liquid; 4, adding activated carbon into an organic phase, stirring for 40 minutes, filtering the obtained product; 5, dissolving sodium iso-octoate into an ethanol solution; and 6, crushing dried cefoxitin sodium into superfine powder by using an air flow. The invention also discloses a cefoxitin sodium superfine-powder preparation which comprises special cefoxitin sodium superfine powder. According to the preparation method, the purity of cefoxitin sodium is greatly improved, so that the cefoxitin sodium has the advantages of high purity, less impurities, small particles, large specific surface area, good solubility, good activity and the like.