Abstract:A chitooligosaccharide Cr (Ⅲ) complex was prepared using water soluble chitooligosaccharide and Cr (Ⅲ) ion as substrates and the effects of four factors, including pH value, temperature, substrate concentration and reaction time, on the forming of the complex were investigated. Structure analysis of the complex with IR and UV-Vis spectrophotometric methods showed that the chitooligosaccharide Cr (Ⅲ) complex had high stability and formed via the -NH2 group. The mass percent of Cr reached 25.04%.