Abstract: The hydrolysates from sea cucumber(Stichopus japonicus)guts were prepared by using neutrase. The crude Maillard reaction products of hydrolysates(MRPs-C)were obtained by reacting with ribose. The sample of MRPs-C was separated into four fractions,including MRPs-Ⅰ(>5 kDa),MRPs-Ⅱ(3~5 kDa),MRPs-Ⅲ(1~3 kDa)and MRPs-Ⅳ(<1 kDa)by ultrafiltration. The fractions were compared by chroma ticity,UV absorption,fluorescence intensity and degree of browning. The antioxidant capacity of each fraction was evaluated by DPPH,ABTS⁺radical scavenging assay,reduction ability,Fe²⁺ chelating and linoleic acid peroxidation assay. The results showed that the MRPs-Ⅰ had higher browning degree,UV absorption and fluorescence intensity than MRPs-Ⅱby 5.0,2.7 and 1.1 times,respectively. The other fractions showed lower browning degree than those of MRPs-Ⅰ and MRPs-Ⅱ. The MRPs-Ⅳ showed the highest abilities of free radical scavenging reduction ability,Fe²⁺ chelating and lipid peroxidation inhibition ability. The scavenging ability against ABTS⁺radical and DPPH reached to 4.56 Trolox equi/μL sample and 47.56%,respectively. These results suggest that the fraction above 5 kDa had more contribution to browning degree,UV absorption and fluorescence intensity in the MRPs of hydrolysates from sea cucumber gut,while the fraction lower than 1 kDa has more contribution to their antioxidant capacity.