Abstract: According to the problem that a gas explosion accident occurred in the underground coal mine would easily cause a large number of the casualties, a large mine roadway test system was applied to study the damage effect of the SD rats within different propagation distances after the explosion of 100 m3 gas air mixed gas occurred. The study showed that the explosive impact damage from the gas explosion occurred was the main cause of the animal death. Even at a far distance of 240 m,the SD rats would be killed due the explosion impact. During the 100 m3 gas explosion process in the underground mine,the explosion flame had an impact range of 40 m. The SD rats in the cages set within the 40 m had the explosion impact damage and also were damaged by the high temperature burning. The conclusion of the study could provide important theoretical basis to the emergency rescue and rescue of the gas explosion accident occurred in the underground coal mine.