The effect of oxygenated additive on particle emission is investigated. Particle size distributions in exhausts from a diesel engine fueled by the blended fuel with different proportions of oxygenated additive are measured by a scanning mobility particle sizer and an aerodynamic particle sizer. Coupled with this, emissions of carbon monoxide, hydrocarbon and nitrogen oxide are also measured with an infrared analyzer, a flame ionization detector and a chemiluminescent analyzer respectively. Results show that there is an effect of oxygenated additive on the particle size distribution from diesel engine. Oxygenated additive can significantly reduce particle emission level and slightly modify emission concentrations of carbon monoxide , hydrocarbon and nitrogen oxide.