Owing to increasing oil price caused by risk of oil depletion, many researchers have focused to develop various alternative energies. Biodiesel is one of those energies, which has been a hot-issue recently in automotive industries. Because biodiesel has similar characteristics as diesel, it is possible to use present gas stations, facilities and engine without any modification. It has also an advantage that the emission of biodiesel is lower than conventional diesel engine because it contains oxygen in the fuel. However biodiesel has some problems such as corrosiveness and high viscosity. Therefore, in this study, an experiment was conducted to use biodiesel fuel to solve these problems, and the characteristics of combustion and emission were evaluated according to the use of biodiesel blended with diesel fuel and it was compared with diesel fuel. As a result, we found that biodiesel has benefits of reduction in CO2 and PM emissions compared to diesel fuel.