Abstract: Collagen peptides from Lophius litulon skin had been extracted by using pepsin with orthogonal design. The composition of Lophius litulon skin, amino acid composition and UV absorption of the collagen peptides were analyzed. And four representive free radical systems were selected to evaluate the free radicals scavenging effection of Lophius litulon skin collagen peptides in vitro. The results showed that the crude protein in skin was 28.1%, the optimal preparation process of collagen peptides from Lophius litulon skin was under this condition, that the pepsin addition was 1%, the ratio between fish skin and solvent was 1∶20, extracting for6 h at the temperature of 5℃, and the Hyp yield of extraction was 11.67%. Ultraviolet Spectrum and amino acid analysis on collagen peptides showed that the maximum absorption peak was being 232 nm and the proportion of Gly was 36.61%, Pro with Hyp was 16.86%, the proportion of Phe, Cys and His were less than 1.1% respectivly.The collagen peptides showed a certain capacity on free radical scavenging and reducibility, which was positive correlation with concentration of collagen peptides. The free radical scavenging rate of ·O, DPPH·, O-2·and reducibility of Fe3 +respectivly were 70.48%, 68.78%, 48.33% and 0.676 at the collagen peptides concentration of 10mg/mL.