Abstract: The tobacco stalk was carbonized under different temperatures from 100 ℃ to 800 ℃, and then the basic physical and chemical properties of biochars were measured. The results showed that the mineral micro-element contents of tobacco-stalk biochar were increased with the increase of pyrolysis temperature at 100-400 ℃ and kept relatively stable at 400-500 ℃. Mineral macro-element contents were showed overall an increased trend with the pyrolysis temperature rise. The contents of carbon (C) and nitrogen (N) were increased gradually from 100 ℃ to 300 ℃ and then were declined from 400 ℃ to 800 ℃, and the C/N ratio was relatively stable at 300-500 ℃. With the increase of pyrolysis temperature, surface functional groups of tobacco-stalk biochar get condensed and its aromatization degree was heightened. With the pyrolysis temperature rise, the porosity of tobacco-stalk biochar was increased first and then decreased. The BET specific surface area, pore size and pore volume of tobacco-stalk biochar were the highest at 400-500 ℃. The mesopores were the main type of pores in tobacco-stalk biochar and mainly consisted of ink-bottle-like pores. The tobacco-stalk-biochar had higher macro- and micro elements, stable C/N, and complex pore structure at 400-500 ℃.