Pine sawdust, which was mixed with deionized water at a mass ratio of 1 to 12, was hydrothermally upgraded in an autoclave reactor under a temperature of 220?260oC and a rotating speed of 150 r/min for 1 h. The characteristics of the generated hydrochar were analyzed to investigate the effect of hydrothermal temperature on the fuel properties, combustion characteristics and kinetic parameters. The results show that the carbon content and heating value of the hydrochar were increased with the hydrothermal temperature. At a hydrothermal temperature of 260oC, the carbon content was increased from 48.10% to 69.05% and the heating value was improved from 19.12 MJ/kg to 26.66 MJ/kg. According to the literature, the variation trend was similar to those of other biomass, whereas the rising rate was a little different. Based on the results from the HPLC and GC-MS, the decarboxylation, dehydration, polymerization and aromatization happened simultaneously in the hydrothermal upgrading of pine sawdust. During the hydrothermal upgrading process, the macromolecular substances were decomposed into small molecules including gas products and organic acids because of these reaction. The results from the TG analysis show that the hydrothermal upgrading was beneficial for improving the ignition performance of the pine sawdust. The combustion temperature which presented the maximum combustion rate kept decreasing with the hydrothermal temperature. However, the time needed to burnout all the sample was increased with the hydrothermal temperature. According to the Arrhenius law, the combustion of pine sawdust could be characterized by the second-order reaction, while that of the hydrochar was characterized by the first order reaction with an activation energy of 33.68 kJ/mol. All these results indicate that the hydrothermal upgrading could improve the energy density and combustion performance of pine sawdust.