Abstract: Anticipatory selfdefense refers to defensive strikes conducted by a nation before an armed attack occurs against it, which is not in coincidence with the regulation on international law that a nation cannot invoke the right of selfdefense until an armed attack occurs against it. However, the new condition such as the emergence of nuclear weapons and terrorism severely challenges the regulation, under which the anticipatory selfdefense appears to be reasonable. Therefore, anticipatory selfdefense right should be admitted partially and the standards for judging whether a behavior belongs to legal anticipatory selfdefense should be established to avoid abuse.