In this study, the yield of conversion process of plastic and biomass wastes has been investigated using the pyrolysis process. To study the pyrolysis process and its yield, a quadratic model has been adopted and the coefficients of the model have been identified from the theoretical and experimental work. The pyrolysis of biomass and plastics has been analyzed through the kinetic model. The model has predicted bio-oil, bio-gas, and bio-char yields. Through kinetic model analysis, thermodynamic parameters have been identified. The Arrhenius coefficient of reaction rate constant has been calculated from the activation energy and absolute reaction temperature. The enthalpy, Gibbs free energy, and entropy of reaction have also been calculated. The activation energy has been observed to vary from 144.9 to 158.5 kJ/mol. The Arrhenius coefficient of reaction rate constant has been identified as 0.000779 per minute. The enthalpy and Gibbs free energy have been observed to have values of 154.35 and 103.65 kJ/mol, respectively. The bio-oil yield has been observed to vary from 60% to 80% of the total yield. For bio-char production, the weight percentage of bio-char has been found as 2 to 3 percent of the total yield. Bio-gas has been found as 10%–25% of the total yield. Therefore, the addition of plastic for pyrolysis can make a positive contribution to the quality of syngas and bio-oil in terms of high heating value, efficiency, and energy output.