In the present study, the thermal decomposition kinetics of tincalconite was investigated by using thermo gravimetric (TG) and differential thermal analysis (DTA) data. The modified form of asymptotic expansion of the temperature integral ∫_x^∞(e^–x/x²)dx, which is employed in a wide range of x = E/RT ratios, was used to perform the kinetic analysis. An empirical model was suggested for calculation of activation energy for non-isothermal decomposition kinetics of solids. The calculation of activation energy of tincalconite was carried out by means of different methods. It was determined that the process takes place in two steps and fits a first order reaction kinetic model. The results obtained from five methods were generally in good agreement.