The vasorelaxation and cholesterol reducing activities of marine collagen oligopeptides( MCOP) were investigated. The vasorelaxation activity of MCOP was evaluated through determination of the secretion of nitric oxide( NO) in human umbilical vein endothelial cell( HUVEC). The results showed that MCOP could increase the secretion of NO in all the test groups,and the vasorelaxation activity of MCOP exhibited a dose-dependent relationship. At the concentration of 12g / L,the effect was the most significant( P < 0. 01). The secretion of NO 1 h after addition of MCOP was higher than that 2 h after addition. The cholesterol reducing activities of MCOP was evaluated by observing the influence of MCOP on expression of low density lipoprotein receptor( LDLR) and 3-hydroxy-3-methylglutaryl coenzyme A reductase( HMGCR) genes. The results showed that after treatment with MCOP for 24h,LDLR mRNA levels were obviously increased in all test groups( P < 0. 05,P < 0. 01) except for 2g / L MCOP group,with LDLR mRNA level in 4 g / L of MCOP group increased the most( P < 0. 01). HMGCR mRNA levels were all decreased in all test groups( P < 0. 05,P < 0. 01),with HMGCR mRNA level in 6g / L of MCOP group decreased the most. The results in this research indicated that MCOP exhibited vasorelaxation and cholesterol reducing activities.