In recent years, with the growth of population and shortage of fossil energy, the environmental pollution problem has become more severe. Eucalyptus planted in south China is a kind of biomass resource with large quantity and high quality. The thermochemical conversion of biomass (pyrolysis, gasification, or combustion) is one of the most promising non-nuclear forms of future energy. It is a renewable source of energy and has many advantages from the ecological point of view. Pyrolysis of wood is a very complicated physical and chemical process which can transform biomass into useful fuel, such as bio-char, bio-oil and gas. Studying its thermo-physical properties is of great significance for the design of the equipment, control of process parameters and quality of the product. In the self-designed fixed bed pyrolysis device, the eucalyptus wood chips were paralyzed in the temperature range of 150~850℃. The remaining bio-char proceeds to be tested for the thermal parameters, including solid yield, bulk density, volume energy density, specific heat and heat conductivity coefficient. The results showed that with the increase of temperature, the solid yield was decreased and the weight loss rate in temperature range of 150~350℃ was up to 31.40% per 100℃;the lower heating value (LHV) of samples was increased gradually. The LHV of bio-char at 750℃ was 95.53% higher than that of the raw eucalyptus. Bulk density was decreased first and then increased while the volume energy density (VED) was increased in the whole experimental temperature range. The VED of bio-char at 750℃ was up to 63.21% more intensive than the raw material. The specific heat and heat conductivity coefficient were closely related to the moisture content and pores structure in bio-char. With the increase of treated temperature, the specific heat of sample presented a U-shaped tendency which was decreased firstly and then increased significantly. The heat conductivity coefficient was increased according to exponential growth after slight decrease. The fitting equations of specific heat Cp and heat conductivity coefficient λ with temperature were obtained and the fitting degrees R2 were 0.9320 and 0.9953, respectively.