Abstract: AIMTo study the crystalline characteristics of ceftezole sodium. METHODSCeftezole sodium crystals were obtained from different solvents. X-ray diffraction, DSC, TGA, etc were used to analyze the crystals. RESULTSCeftezole sodium crystal was easily obtained in isopropanol-water mixture. It consists of ceftizole sodium monohydrate, which consists of type I and type II two different crystal forms. Powder X-ray diffraction patterns showed differences between type I and the type II crystal forms. Peaks at 8° and 18° in diffractograms of the type I, but at 9° and 18.6° in the type II could be observed. Water molecules in different crystal forms had different combining condition. They lost during 35～117℃ in the type I form, but lost during 110～160℃ in the type II form. CONCLUSION Structure of ceftizole sodium monohydrate crystal obtained in different circumstance could be some vary, which influence upon the thermal stability of the compound. The type I crystal form is more stable than the type II.