Thermal reaction of paraffin with oxidizers could provide valuable information concerning the regression rate and combustion efficiency of paraffin-based fuels. In this paper, thermogravimetric–differential scanning calorimetry experiments were carried out for paraffin under O2 and N2O atmosphere, and the thermal reaction kinetics of paraffin under different pressures of O2 and N2O was estimated through the non-isothermal measurements and model-free isoconversional methods. The results show that the oxidation of paraffin under O2 and N2O atmosphere represents the multistage reaction process; the obtained activation energy (E a) is much close by using different model-free isoconversional methods, and paraffin is easier to be oxidized under O2 because of the lower E a and lower reaction temperature; Pressure plays a positive effect on the oxidation of paraffin, especially under O2 atmosphere.