<p>The energy and exergy performances of the corn straw and Silicon Carbide (SiC) in the microwave heating process are crucial to sufficiently utilize crop residues for mitigating environmental pollution, promoting waste value, and improving farmer incomes. In this study, the comprehensive energy and exergy performances (the absorbed energy, energy efficiency, absorbed exergy, and exergy efficiency) of the mass ratio (SiC to corn straw), microwave power, and reaction chamber volume were compared and analyzed. The effect of the mass ratio of SiC to corn straw on energy and exergy performances based on the experimental data was newly studied. Also, the parametric analysis of the microwave power and reaction chamber for the microwave heating process of corn straw assisted by SiC was conducted. The findings indicate that increasing the mass ratio of SiC to corn straw from 0 to 1 significantly improves performance metrics: final absorbed energy increased from 5466 J to 6195 J, energy efficiency from 9.1% to 20.7%, absorbed exergy from 1102 J to 1312 J, and exergy efficiency from 1.8% to 4.4%. Similarly, increasing microwave power from 400 W to 600 W enhanced final absorbed energy from 5752 J to 6195 J, energy efficiency from 11.1% to 20.7%, absorbed exergy from 1177 J to 1312 J, and exergy efficiency from 2.3% to 4.4%. Conversely, enlarging the reaction chamber from 100 mL to 300 mL resulted in decreases: final absorbed energy dropped from 5758 J to 5700 J, energy efficiency from 11.6% to 9.0%, absorbed exergy from 1122 J to 1118 J, and exergy efficiency from 2.3% to 1.8%. These results underscore the substantial influence of the mass ratio on energy and exergy performances, while indicating that the reaction chamber volume has a minimal impact on the performances.</p>