The effect of fuel properties on diesel combustion and exhaust emissions characteristics were investigated by using Computational Fluid Dynamics which includes detailed elementary reaction processes. Chemical effects are examined by increasing the content of aromatic components and physical effects are done by deactivating the evaporation characteristics. As a result, the soot formed is increased with the increase of aromatic component up to 40% at constant physical properties. When evaporation properties were deteriorated by replacing original physical properties with those of higher HCs, soot emission was decreased due to longer ignition delay time.