Swim bladder is one of marine potential byproducts for alternative source of collagen. This study aimedto optimize hydro-extraction and characterized collagen. Extraction optimization of collagen was determinedusing Box-behnken design response surface method with three variables: CH3COOH concentration, soakingtime and extraction time to yield response. Hydro-extraction collagen was characterization based on theamino acid content, SDS-PAGE, FT-IR and DSC. Acording to the result, the concentration had significantlyinfluence yield. Optimum extraction conditions were variable combinations of acetic acid concentration of0.1 M, for 1 h and hydro-extraction time of 1 h to produce the highest yield 63.35%. collagen was classifiedas type I collagen ...