Abstract：Fish scale based biochars （FSBCs） were prepared from tilapia fish scale by one-step carbonization and KOH activation method. The pore structure， morphology and surface chemical properties of the FSBCs were analyzed using XRD， SEM， FTIR， Boehm method， etc. The results showed that the FSBC-1 prepared at 650 ℃ possessed the maximum amount of surface oxygen-containing groups， including 0.3102 mmol·g-1 of phenolic hydroxyl group， and the FSBC-3 prepared at 850 ℃ possessed the highest specific surface area （SSA） and pore volume， which were 3370 m2·g-1 and 1.91 cm3·g-1， respectively. Static adsorption experiments demonstrated the adsorption capacities of FSBC-3 for toluene and acetone were 12.75 mmol·g-1 at 3 kPa and 16.74 mmol·g-1 at 20 kPa， respectively， at 298 K. Based on the data of dynamic adsorption experiments， the adsorption mechanism was analyzed. For low concentration of toluene （non-polar molecule）， the adsorption capacity might be mainly affected by SAA and micropore volume of FSBCs， while for low concentration of acetone （polar molecule）， the adsorption capacity might be mainly affected by the amount of phenolic hydroxyl groups on the surface of FSBCs. This study systematically investigated the preparation of FSBC， and the adsorption performance and mechanism of FSBCs for two typical volatile organic compounds （VOCs）， toluene and acetone. It may provide guidance on the preparation of high-efficient VOCs adsorbents.