Abstract: As a typical wide-range fuel,aviation kerosene/diesel blended fuel has the potential to improve ignition ability and low-temperature start,and less impact on the structural reliability for diesel engine. Based on an electric heated constant volume combustion vessel,the effects of different aviation kerosene blending ratios on the blend fuel spray,ignition and soot emission were studied using optical diagnosis methods including schlieren,wide-area low-pass luminescence and high-frequency backlight extinction. The results show that blending diesel fuel in aviation kerosene is beneficial to improve the ignition ability,but leads to increase soot emission and produce obvious infrared signals. Specifically,with the increase of the diesel blending ratio,the non-evaporating spray volume hardly changes,but in the high-temperature evaporation environment,both spray cone angle and volume decrease slightly. The addition of 25%（volume fraction） diesel can significantly shorten the ignition delay period,and the soot area and soot mass are similar to those of pure kerosene. With the further increase of diesel components,both soot area and soot mass increase significantly. Furthermore,blending 25% diesel in the aviation kerosene fuel can significantly improve the ignition performance of blending fuel,and maintain a low level of soot emission when the fuel is applied in diesel engines. Blending less ratio of diesel fuel into the aviation kerosene is suitable for use in aero engines,thus becomes a single fuel with more potential than pure aviation kerosene.