The　aim　of　this　study　was　to　characterize　the　collagens　from　the　body　of　surf　clam　shell　(Coelomactra　antiquata).　Guanidine　hydrochloride　and　pepsin　were　used　to　extract　collagens.　Guanidine　hydrochloride　soluble　collagen　(GSC)　and　pepsin　soluble　collagen　(PSC)　were　separately　isolated　from　the　body　of　surf　clam　shell.　Results　showed　that　the　moisture,　protein,　carbohydrate,　and　ash　contents　of　the　body　of　surf　clam　shell　were　82.46%,　11.56%,　3.05%,　and　2.38%,　respectively,　but　the　fat　content　was　only　0.55%.　The　yields　were　0.59%　for　GSC　and　3.78%　for　PSC.　Both　GSC　and　PSC　were　composed　of　α　1　and　α　2　chains　and　a　β　chain,　however,　GSC　and　PSC　showed　distinct　differences　from　each　other　and　the　type　I　collagen　from　grass　carp　muscle　on　sodium　dodecyl　sulfate-polyacrylamide　gel　electrophoresis　(SDS-PAGE).　GSC　and　PSC　contained　glycine　as　the　major　amino　acid　and　had　imino　acid　of　150　and　155　residues/1000　residues,　respectively.　Fourier　transform　infrared　spectroscopy　(FTIR)　spectra　of　GSC　and　PSC　revealed　the　presence　of　a　triple　helix.　The　GSC　appeared　to　have　a　dense　sheet-like　film　linked　by　random-coiled　filaments　and　PSC　had　fine　globular　filaments　under　scanning　electron　microscopy　(SEM).　The　maximum　transition　temperature　(T　max　)　of　GSC　and　PSC　was　33.05　◦　C　and　31.33　◦　C,　respectively.　These　results　provide　valuable　scientific　information　for　the　texture　study　and　development　of　surf　clam　shell　or　other　bivalve　mollusks.　©　2019　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.