Nowadays, when the aviation sector is of primary importance for both civilian and military purposes, efforts to improve the power generation mechanisms required for aircraft are of current importance. Researchers are working to make gas turbine engines operate more efficiently, cost-effectively and environmentally friendly. In this study, the performance values of a high bypass ratio gas turbine engine at different biofuel addition rates were numerically analyzed. In the study where JP4 was used as jet fuel, a mixture of 25% Triglyceride (C6H8O6) and 75% Methanol (C1H4O1) was used as biofuel. In the study, the biofuel ratio was increased by 10% molar intervals. The results showed that as the biofuel ratio increased, the total pressure and exergy at the core nozzle exit of the turbofan engine increased parabolically. In addition, the increased engine performance data was reflected in the thrust produced and the net thrust increased as a result of the biofuel addition.