Abstract: In this study, three core-shell biomass including coconut shell, peanut shell and hazelnut shell were pyrolyzed to prepare pyrolysis carbon under different pyrolysis temperatures（400 ℃, 550 ℃ and 700 ℃）. Then pyrolysis carbons were modified by acid（HNO₃） and alkali（KOH）. The physical and chemical properties including electrical conductivity, element composition, ash content, specific surface area, scanning electron microscope and fourier transform infrared spectroscopy（FTIR） of pyrolysis carbons and modified pyrolysis carbons were characterized. The results show that the effect of pyrolysis temperature on carbon yield of coconut shell is not obvious, while the hazel shell carbon yield is the highest. With the increase of pyrolysis temperature, the electrical conductivity and contents of ash and fixed carbon of pyrolysis carbons are enhanced. The coconut shell carbon obtained at 700 ℃ achieves the greatest electrical conductivity（6.24×10~5 μS/cm）. Meanwhile, the carbonization degree of pyrolysis carbon also becomes higher, but the molar ratios of H/C, O/C and（O+N）/C decrease, which indicates the higher stability and aromaticity. Moreover, the pore sizes of pyrolysis carbons decrease slightly while the specific surface area increase significantly. The peanut shell carbon obtained at 700 ℃achieves the largest specific surface area（393.10 m~2/g）. The oxygen-containing functional groups in pyrolysis carbons decrease due to decarboxylate and carbonylation. The acid（HNO₃） and alkali（KOH） modification have significant influences on characteristics of pyrolysis carbon. After acid modification, the surface of pyrolysis carbon becomes more loose and has abundant pore structure, and the number of acidic functional groups（C==O） increase. The electrical conductivity of pyrolysis carbons obtained at 400 ℃ increase significantly, while those obtained at 550 ℃ and 700 ℃ decrease. After alkali modification, pyrolysis carbons own abundant pores and clear fibrous structures, and the number of oxygen-containing functional groups（—OH） increase. Except for coconut shell carbon obtained at 550 ℃ and peanut shell carbon obtained at 400 ℃, the electrical conductivities of other pyrolysis carbons decrease.