Exergy analysis is useful to evaluate the effectiveness of energy conversion process. This study is aimed to evaluate the effectiveness of oil palm empty fruit bunch conversion by pyrolysis process using the exergy analysis compared to the theoritical of the cellulose pyrolysis. The effect of pyrolysis temperature was evaluated based on the amount of selected syngas produced. The results show that Increasing the temperature of pyrolysis from 473 K until 723 K will increase the concentration of H2 and CH4, but it will reduce the concentration of CO. Based on exergy efficiency, the optimum composition of gases that can be produced in the pyrolysis process of 1 mol cellulose are 3 mol of H2, 5 mol of CO, and 1 mol of CH4 at a temperature of 723K. The maximum amount of exergy efficiency is 96.33% in the reaction 2. Based on Gibbs free energy, the maximum value of hydrogen will be produced start at temperature 628K.