In this study, spray characteristics of biodiesel blending with di-n-butyl ether (DBE15, DBE30) were investigated by experiment and analysis and compared with diesel. Spray characteristics parameters including spray tip penetration, spray cone angle, maximum spray width and spray tip velocity were used to compare under different injection pressures and ambient pressures. The spray images were analyzed according to light intensity level, while the gas entrainment mass and equivalent ratio were analyzed by empirical model. The results showed that the spray tip penetration of biodiesel added with DBE was reduced and the spray cone angle and maximum spray width were increased. The range of light intensity level of biodiesel was the narrowest, while the light intensity level of biodiesel-DBE blends was similar to that of diesel. Empirical models showed that biodiesel shows poor gas-fuel mixing. DBE30 had a larger gas entrainment mass and a lower equivalence ratio, similar to diesel. It was proved that the biodiesel added with DBE enhanced the gas-fuel mixing. (C) 2019 Published by Elsevier Ltd.