The diesel engine is excellent in economic and thermal efficiency, and is widely used as a power source for industries and automobiles. However, the problem of environmental pollution caused by exhaust gas has recently become serious and the development of alternative energy resources is urgently required due to depletion of fossil fuel. Because biodiesel is similar in properties to light oil, it is being used as fuel for diesel engines by replacing or mixing conventional light oil. As the blending of biodiesel fuel in diesel increases, the emission of harmful substances is decreased as compared with the general diesel fuel, and the supply is increasing. In this study, the effects of biodiesel fuel on engine power and exhaust gas were investigated, and empirical formulas for various NOx and Smoke exhaust gases were derived based on biodiesel blending fuel.