In this study, the spray characteristics of blending fuel with diesel fuel and high viscosity biodiesel fuel was investigated. The research was performed for the effect on biodiesel fuel blending ratio and injection pressure for the spray behavior. The experimental process of spray injection was analyzed with LDPAlaser diffraction particle analyzer). In addition, spray atomization characteristics were researched with SMD(Sauter mean diameter) and droplet distribution on various injection pressure conditions. Fuel containing high viscosity biodiesel fuel has some different spray behaviors on account of the viscosity and surface tension. Though this experimental result, we found that the increase of injection pressure enables SMD to get smaller, but the increase of blending ratio makes SMD larger.