Abstract: The distillation residues from bio-oil and the pyrolysis char obtained at different temperatures were investigated with FT-IR, Raman spectra and TGA. The results show that the distillation residues from bio-oil consist of aliphatic, aromatic and oligosaccharides. The process of thermal weight loss of distillation residues from bio-oil in nitrogen can be separated into three stages. The first is the volatilization of low-boiling point compounds from ambient temperature to 145℃. The second is the pyrolysis, oxidation and polymerization of the heavy compounds at higher temperature and the last is the formation and combustion of coke. The graphitic carbon fraction increases with increasing the carbonization temperature while the disordered carbon amount decreases.