Abstract: Selenium-chelating corn oligopeptide was prepared by using corn oligopeptide and sodium selenite. The basic physical and chemical properties of moisture,acid soluble protein,total nitrogen and molecular weight distribution were analyzed. Taking the molecular weight and selenium content as indicators,the effects of temperature,pH and simulated gastrointestinal digestion in vitro were investigated. The results showed that the chelating rate was 54.25%±0.24%,the yield was 53.02±0.17%,the moisture content of the product was 7.46%±0.07%,the content of acid soluble protein was 16.38%±0.03%,the total nitrogen content was 21.17%±0.35%,and the molecular weight below 1000 u was 85.1512%. At the temperature of 25~100℃,the proportion of molecular weight less than 1000 u changes no more than 7%,and the content of selenium was not less than 70%. In the pH=2~12,the maximum change of the ratio less than 1000 u was no more than 16%,and the content of selenium was not less than 75%. After digested with pepsin,trypsin and the two enzymes together,the molecular weights less than 1000 u exceed 5%,7% and 8%,and the selenium content was more than 70%. This results showed that selenium-chelating corn oligopeptide had a certain stability in thermo,pH and digestion.