Biomass activated carbon (BAC) was produced from ginger stems by carbonization and activation presented high specific surface areas and mesoporous structures. The carbonization temperature of the ginger stems were controlled within 500~900℃. The optimal carbonization condition is as follows: carbonization temperature of 700℃, carbonization time of 6 h. The determined optimum activation condition is: temperature of 800℃, activator of KOH and carbonized product/alkali ratio of 1:4 (w/w). The carbonization yield, BAC yield and Brunauer-Emmett-Teller (BET) surface area were measured and the adsorption performance of BAC to nitrogen was investigated. The results showed that the nitrogen adsorption isotherm curve was as type I isotherm. It was finally determined that the BET surface area was 660 m²/g under the abovementioned optimal conditions of carbonization and activation. The FESEM analysis indicates that the obtained BAC is of micropore structure.