Blood (livestock blood) is a cheap and readily available biomass material with a relatively high protein content.In this study, bio-nitrogen doped activated carbon (BN-AC) was prepared by chemical activation method with nitrogen-rich pig blood as raw material and magnesium chloride as activator.The specific surface area of BN-AC is 283.719 m2/g, and the pore volume is 0.128 cm3/g.The optimum conditions for the preparation of BN-AC were as follows: the mass impregnation ratio of activator to blood powder was 2:1, the impregnation time was 12 h, and the activation temperature was 600 ℃.The forms of biological nitrogen in activated carbon were studied by elemental analysis, Boehm titration, FTIR and XPS.The results showed that the total basicity of 0.720 mmol/g, and acidity of 0.313 mmol/g of the BN-AC.The surface of the precursor has only one Pyrrolic N, and the surface of BN-AC contains Pyridinic N, Pyrrolic N and Graphitic N, the N content of the precursor was successfully preserved.BN-AC has higher methylene blue and iodine adsorption values than ordinary activated carbon.