Highspeed photography was used to study the macro spray characteristics of biodiesel, 0# diesel and the mixed fuel with different proportion of biodiesel. It showed that the spray angle got smaller with the proportion of biodiesel increased at the initial stage of injection. During the injection process, the spray angle of biodiesel and fossil diesel fuel had little differences. Penetration rate of fossil diesel fuel and biodiesel were growing larger till stable. With the time increasing, the penetration rate of biodiesel became larger than that of fossil diesel fuel. With the proportion of biodiesel increasing, the duration of injection became longer. Especially, when the percentage of biodiesel was over 50%, the fuel injection duration increased significantly. 