Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from diesel engine are recognized main cause which influenced environment strong. In this study, the potential possibility of biodiesel and oxygenates additives (dimethoxy methane) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel(biodiesel 90vol-% + DMM 10vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 70% at 2500rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emissions withg biodiesel and DMM blended fuel had been increased compared with commercial diesel fuel.