The influence of different acid treatment on protein yield (PY), hydroxyproline (HYP) content, protein distribution and viscosity of fish gelatin was investigated in this paper. The results showed that proton concentration greatly affected the gelatin extraction rate. The protein yield of acetic acid, citric acid and HCl were 13.50%~20.55%, 10.52%~20.01% and 4.32%~20.86%, respectively. The highest protein yield and hydroxyproline content using the three acids were similar, while the corresponding viscosity was different. Gel electrophoresis results showed that the extracted gelatin contained mostly α-chains and β-chains, and the gelatin with more α-chains showed better viscosity properties.