A new approach is proposed to obtain the kinetic parameters of biomass pyrolysis mixed with calcium catalyst. This approach involves the optimization of least squares (LS) with the Coats-Redfern integral method to avoid mathematical biases that may appear when applying the linear regression approach. The method was applied to the TGA data of pyrolysis of corn cob and corn cob mixed with 20 or 40 % by weight of CaO or CaCO3 under N2 atmosphere at temperatures between 25 and 700 °C. For raw cob, r2 reaches 0.997. For corn cob mixed with 20 % by weight of CaO or CaCO3, r2 reached 0.996-0.998, and for 40 % by weight, r2 reached 0.836-0.957. Applying this method, the activation energy (EA) value of the raw cob pyrolysis is 58.35 kJ mol-1, while the addition of CaO or CaCO3 increases the EA to 69.33 and 66.07 kJ mol-1, respectively. The method is simple to use and allows reliable values of kinetic parameters.