The invention belongs to the field of medicines and relates to a cefmetazole crystal-form compound and a preparation method thereof. The cefmetazole crystal-form compound and the preparation method thereof, provided by the invention, are used for improving the quality stability of cefmetazole and safety in clinical medication. Shown by parameters such as melting point, IR and PXRD, the cefmetazole crystal-form compound is different from any novel crystal form in the prior art; compared with the existing cefmetazole on the market, the crystal-form compound has the advantages that the content of related substances is extremely low, the stability is high, and the content of related impurities is free of obvious increase along with the prolongation of storage time, so that the cefmetazole crystal-form compound is suitable for serving as a standard in detection analysis or quality control.