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In the processes of preparation and application of nanomaterials,the thermal decomposition of nanoparticles is often involved.There is great difference in the thermal decomposition kinetics between nanoparticles and the corresponding bulk substances.A general theory of improvement about the thermal decomposition reaction kinetics of nanoparticles,developed over the past 10 years,was presented in this paper.In experiment,the thermal decomposition kinetics of nano-sized calcium oxalate(nano-CaC2O4)with different particle sizes was studied by means of Thermogravimetry Analysis(TGA)at different heating rates.The values of the apparent activation energy and the pre-exponential factor were evaluated using the equation of Iterative Kissinger-Akahira-Sunose(IKAS)and its deformations.The regularities of effect of particle size on the apparent activation energy and the pre-exponential factor were summarized,which are consistent with the thermal decomposition reaction kinetics theory of nanoparticles.Based on the theory,the method of obtaining the surface thermodynamic properties by the determination of kinetic parameters was presented for the first time,and the partial molar surface enthalpy and partial molar surface entropy of nano-CaC2O4 were obtained.Theoretical and experimental results show that the particle size has notable effect on the thermal decomposition kinetics.The decomposition apparent activation energy is influenced by the partial molar surface enthalpy and the pre-exponential factor by the partial molar surface entropy.With the decreasing of particle size,the partial molar surface enthalpy and partial molar surface entropy increases,while the apparent activation energy and pre-exponential factor decrease.Furthermore,the apparent activation energy,the pre-exponential factor,the partial molar surface enthalpy and the partial molar surface entropy are linearly related to the reciprocal of particle diameter,respectively.