Micro-explosion characteristics of soybean oil droplet were investigated using high speed backlight imaging technique at ambient temperature 873 K, 923 K and 973 K. Experimental results indicate that soybean oil droplet underwent transient heating phase, micro-explosion evaporation phase, equilibrium evaporation phase, and residue evaporation phase at all the studied temperatures. The evaporation rate of equilibrium evaporation phase is increased when the temperature increased. However, a decrease for the evaporation rate of residue evaporation phase. Homogeneous and heterogeneous nucleation are observed at all temperatures, homogeneous nucleation lead to strong micro-explosion and heterogeneous nucleation lead to weak micro-explosion. Moreover, micro-explosion strength increased when the ambient increased. It was found that the micro-explosion occurred at the end of droplet evaporation, this is one of the reasons for the poor atomization characteristics of bio-oil in the engine. More importantly, the evaporation induced vapor cloud is observed at 973 K, this is mainly due to the non isothermal condensation caused by Stefan outflow. (C) 2019 Elsevier Ltd. All rights reserved.