Only a few studies of heterosolvate are reported in the literature. In this article, heterosolvates of cefodizime sodium were prepared in water/ethanol binary solvent mixtures and characterized. Through thermal analysis and composition determination, we deduced that both water and ethanol molecules participated in the forming of crystal lattice. The general chemical name of heterosolvates may be defined as cefodizime sesquihydrate sesquiethanolate. Then, the studies on infrared ATR, and Raman spectroscopy provided a strong evidence of intermolecular hydrogen bonds. Further, the crystal structure of solvates was analyzed by the powder X-ray diffraction data. The results indicated that the structure differences between solvate and raw material were mainly caused by the solvent effect, leading to forming solvation through intermolecular hydrogen bonding.