The invention discloses a cefoxitin sodium powder preparation for injection. The cefoxitin sodium powder preparation is prepared by the following steps: (1) controlling the temperature, and preparing a sodium-forming agent solution; (2) adding acetone and methyl alcohol to a reaction tank, cooling, stirring under nitrogen protection, adding cefoxitin acid until dissolving, adding activated carbon, decolorizing, filtering, mixing a solvent and washing; (3) controlling the temperature of a crystallization tank, the stirring speed and the nitrogen pressure by molecular assembly and shape optimization techniques for crystal products in a grain process by Hebei Huamin Pharmaceutical Co.,Ltd. in North China, dropwise adding the sodium-forming agent solution, and adding acetone according to a feeding rate form; (4) filtering and drying crystalline liquid, detecting and discharging; and (5) carrying out sub-package of preparations with different specifications, and controlling the environment temperature and humidity to obtain cefoxitin sodium for injection. The cefoxitin sodium for injection, prepared by the preparation method, has good hydrodynamics performance, and is perfect in crystalline form and uniform in particle size distribution; and the color grade, the clarity, the purity and the stability are greatly improved.