Abstract: Oil spill accident in the processes of marine oil exploitation and transportation will pose serious threats to the marine ecological environment. In this study, biochar was prepared from pine sawdust under pyrolysis temperature of 300 ℃, 400 ℃ and 500 ℃ respectively for 2 h, and then modified with hydrochloric acid. The oil adsorption properties of the biochar from seawater before and after modification were analyzed. The results showed that pyrolysis temperature and hydrochloric acid concentration had obvious effects on the oil absorption performance of biochar, and the adsorption amount of pine sawdust biochar was the largest at pyrolysis temperature of 400 ℃ and hydrochloric acid of 5 mol/L, which was 1.96 g/g. After modification, the specific surface area, total pore volume of the modified biochar and the number of oxygen-containing functional groups decreased, but the types of surface functional groups changed little. The oil adsorption process of modified biochar from seawater was in accordance with the pseudo second order kinetic equation(R²=0.998) and Freundlich isotherm model(R²>0.999). The results were helpful for the development of economical, environmental friendly and efficient adsorption materials for the treatment of marine oil spill.