Abstract: Calcium-chelating marine bone collagen oligopeptides(MBCP-Ca) were prepared by using salmon bone as raw material. Taking molecular weight distribution and calcium content as indicators,the effects of temperature,pH and in vitro simulated gastrointestinal digestion on the stability of MBCP-Ca were investigated.Results showed that:MBCP-Ca had good thermal stability. The change of the molecular weight distribution ranges did not exceed 2% and the calcium content of MBCP-Ca showed no significant difference. In the acidic and alkaline conditions,the molecular weights below 1000 u of MBCP-Ca were slightly elevated,but the content did not exceed 8%. The calcium content of MBCP-Ca decreased,but was still higher than 65%. After digested by proteases,the molecular weights below 1000 u of MBCP-Ca were slightly elevated,but the content did not exceed 6%. After digested by pepsin and trypsin together,the calcium content of MBCP-Ca were40.5%. The results indicated that MBCP-Ca had good thermal stability,pH stability and digestion stability and it was a peptide-calcium supplement product with promise.