In this study,the effect of crosslinking method on biological properties of grass carp skin collagen sponge was discussed.Collagen was extracted from skin of grass carp(Ctenopharyngodon idellus)and collagen sponge was prepared from this collagen.Then,this collagen sponge was crosslinked with different methods,such as UV,dehydrothermal,EDC/NHS and glutaraldehyde crosslinking processes.At the same time,the biological and mechanical properties of those collagen sponges,including degree of crosslinking,denaturation temperature,tensile strength and enzymatic sensitivity in vitro,were evaluated and compared.Experiment results indicated that the grass carp skin collagen was type Ⅰ collagen.The degree of crosslinking of different crosslinking methods decreased in the order of glutaraldehyde(72.0%)＞EDC/NHS(32.5%)＞dehydrothermal(29.9%)＞UV(15.6%).Compared with control collagen sponges,the denaturation temperature(67.4 ℃),tensile strength(125.6 kPa)and enzymatic sensitivity in vitro of collagen sponges crosslinked by glutaraldehyde were significantly improved(P＜0.05);EDC/NHS crosslinking could lead to obvious increasing in denaturation enthalpy(6.86 J/g)and moderate improving on tensile strength(98.6 kPa)and enzymatic sensitivity for collagen sponge(P＜0.05).The changes of biological and mechanical properties of collagen sponges after being crosslinked by dehydrothermal and UV crosslinking processes were not notable.The results of FTIR showed that glutaraldehyde crosslinking could improve properties of collagen sponges by forming new covalent bond in triple helix structure of collagen,while EDC/NHS crosslinking do that by forming new hydrogen bonds among collagen molecules.This research shows that glutaraldehyde and EDC/NHS crosslinking could lead to obvious improvement in properties of collagen sponges but the influences on properties of collagen sponges after being crosslinked by dehydrothermal and UV crosslinking processes were limited.