Collagen was extracted from jellyfish (Stomolophus meleagris) and hydrolyzed to prepare collagen peptides. Three fractions (JCP-1<1kDa, 1kDa3kDa) were collected by ultrafiltration from jellyfish collagen peptides and inhibitory abilities of melanogenesis were evaluated using cultured B16 melanoma cells. The results showed three fractions could inhibit intracellular tyrosinase activity, decrease melanin content and enhance glutathione synthesis. Furthermore, they decreased intracellular cAMP levels and suppressed tyrosinase mRNA expression. JCP-2 showed much higher anti-melanogeneic activities than JCP-1 and JCP-3 because of its amino acids composition and molecular weight distribution. Our results indicated JCP-2 could be used as a natural skin-lightening agent in the medicine and food industries.