Abstract: The calibration curve for quantitative analysis of evolved CO₂ during thermal decomposition in a thermogravimetric analyzer coupled with mass spectrometer (TG-MS) was made by the decomposition of pure CaCO₃. The activation energy of the decomposition reaction was calculated from a single experiment using Freeman-Carroll method. Using electron ionization, TG-MS in inert atmosphere was firstly performed to analyze the evolved behavior of gaseous mixture released by thermal decomposition of cigarette paper, to obtain the temperature range of the decomposition reaction of CaCO₃ in cigarette paper, and to build the quantitative method of CaCO₃ of cigarette paper. The results show that the calibration curve for the quantitative analysis of evolved CO₂ by TG-MS is Y =10^-8 X+0.162 9，R² =0.998 2 under He atmosphere at heating rate of 25 ℃•min^-1 and gas flow rate of 200 mL•min^-1. Using the calibration curve, the amount of CaCO₃ in cigarette paper can be determined easily by TG-MS.