A model was proposed to calculate several thermodynamic parameters for the initial-stage sintering of an alumina powder obtained after calcinations at 900 °C for 2 h of a precursor. The precursor was synthesized by an alumina sulphate-excess urea reaction in boiling aqueous solution. The cylindrical compacts of the powder with a diameter of 14 mm were prepared under 32 MPa by uniaxial pressing using oleic acid (12% by mass) as binder. The compacts were fired at various temperatures between 900 and 1400 °C for 2 h. The diameter (D) of the compacts before and after firing was measured by a micrometer. The D value after firing was taken as a sintering equilibrium parameter. An arbitrary sintering equilibrium constant (K a ) was calculated for each firing temperature by assuming K a = (D i -D) / (D -D f ), where D i is the largest value before sintering and D f is the smallest value after firing at 1400 °C. Also, an arbitrary change in Gibbs energy (ΔG a °) was calculated for each temperature using the K a value. The graphs of ln K a vs. 1/ T and ΔG a °vs. T were plotted, and the real change in enthalpy (ΔH°) and the real change in entropy (ΔS°) were calculated from the slopes of the obtained straight lines, respectively. Inversely, real ΔG°and K values were calculated using the real ΔH°and ΔS°values in the ΔG°= -RT ln K = ΔH°-TΔS°relation. The best fitting ΔH°and ΔS°values satisfying this relation were found to be 157,301 J mol -1 and 107.6 J K -1 mol -1 , respectively.