To resolve the precise time of death has an extreme importance in law because it is effective in deciding about the inheritance law and in some subdivisions of criminal law. The more important effect that has been recovered in recent years is determining the time of corpse dissection and using the body limbs for joining to the others because it is morally and legally forbidden to autopsy before death. In the past centuries fight and medical professions and customs had achieved to an agreement about the determining the time of death. But today brain death is a new problem that has made difficult to determine this time. This article has an end to study about the differences of brain death and coma Depose and prove that in the scope of fighter can accept the brain death as a real death.