Abstract: The surface tension, kinematic viscosity, abrasion resistance, oxidation stability and soot emission characteristics of a biodiesel-diesel blend fuel were investigated. The results showed that the surface tension of the blend fuel varies in terms of parabola trend with the increase of biodiesel content and decreases according to a power function with the increase of temperature. The biodiesel exhibits less wear spot diameter and greater maximum bite limit pressure than the diesel fuel. The oxidation stability of the blend fuel is improved obviously when the biodiesel content is 40%～70%. With the increase of the biodiesel content, the viscosity of the blended fuel is increased linearly, while the soot emission, when burned as the engine fuel, is decreased significantly.