Abstract: Pouring water into burning oil, which can trigger acute reaction, is an extremely complicated process. The details can not be captured by experiments. In this paper, the process was reproduced by numerical simulation. The extremely dangerous phenomenon was deeply analyzed and the physical chemistry process after pouring water into burning oil was concisely discussed. Simplified numerical models for the complicated process were established and further numerically tested using open-source FDS fire dynamic modelling software to examine its feasibility. The results indicate that oil gas produced by splashing oil droplets disperses quickly in the vast room along with the flow of hot air. The oil gas can be delivered to the position that is far away from where the splashing oil droplets can reach during an extremely short duration, which makes the dramatic expansion of the flame. However, unwanted damage can be caused by the violent increasing of radiation heat flux of irruptive flame. The results of the simulation can give us deep understanding about the process, so the process may be rationally restrained or utilized in the future.