The kinetic analysis of the thermal degradation of pyrolytic heavy oils obtained from mixed waste plastics by kiln pyrolysis process has been studied by conventional thermogravimetric technique with various heating rates in nitrogen atmosphere. Results of kinetic analysis show that the activation energies are 24.4~26.5 kJ/mol and the reaction orders are 1.0~1.25, respectively. To verify the effectiveness of the kinetic analysis method used in this work, the experimental values were compared with those of the numerical integration results using kinetic parameters obtained in this work. It was found that the kinetic analysis method used in this work gave the reliable kinetic parameters of the thermal degradation of pyrolytic heavy oils.