The thermodynamics of nanocrystalline TiO 2 ceramics during the whole sintering process were analyzed using differential scanning calorimetry (DSC) for different heating rates (10, 20 and 30°C/min). The raw TiO 2 powder was also studied comparably. The DSC and specific heat capacity (C p ) were also studied. The results show that there is no obvious endothermic or exothermic peak at the stage where the maximum densification rate occurred for TiO 2 ceramics. The ordering process induced by the microstructural densification counteracts the disordering process induced by increasing the sintering temperature. The sintering process is a result of combination of the ordering process and the disordering one. The activation energy of nanometer TiO 2 ceramics determined by Kissinger method is 103.8kJ/mol.