Thermal decomposition kinetics of calcium carbonate was studied by non-isothermal thermogravimetric analysis at different heating rates. The reaction mechanism was found to follow a two-dimensional phase boundary-controlled model by model-free and model-fitting methods. Two non-Arrhenius equations (Harcourt-Esson equation and Berthelot-Hood equation) were used to interpret the decomposition kinetics and the results were correlated with those by using the Arrhenius equation. The ambiguous operations in kinetic analysis in the literature, including the determination of reaction mechanism by the shape of thermogravimetry/DTG curves and the correlation of the kinetic parameters of non-Arrhenius and Arrhenius equations, were discussed. Some suggestions were proposed when using non-Arrhenius equations in interpreting solid decomposition kinetics.