Spray characteristics of Ethanol-Fatty Acid Methyl Ester Blends under common-rail injection condition were experimental investigated,by the high speed photography and particle/droplet image analyses(PDIA).The results show that spray cone angle and project area is increased with the increase of ethanol percentage and ambient pressure.Sauter mean diameter(SMD)increases with the increased axial distance at the same radial distance.SMD sharply decreases with the increased injection pressure,the average amplitude is 2μm.SMD of FAME decreases about 3μm after mixing ethanol.Spray characteristics of Ethanol-Fatty Acid Methyl Ester Blends and diesel are similar,thus the engine is rarely modified while fueled with FAME/Ethanol blends.