The composition,antioxidant activity in vitro and inhibition of ACE activity of rapeseed protein hydrolysates(RPH) were analyzed in this paper.The protein hydrolysates were separated by gel filtration chromatography into different components.The relationship of antioxidant activity in vitro and inhibition of ACE activity of different components between the amino acid composition and the molecular weight distribution of the components were discussed.The result shows that the protein hydrolysates have good functional properties in vitro.Among nine peaks separated by Sephadex G-25,peak 2,4 and peak 5 have better functional properties in vitro;these peaks contain higher levels of hydrophobic amino acids and more than 90% of the molecular weight distribution which is lower than 1000.