Abstract: Exploring the limit of justifiable defence in foreign laws is of far-reaching significance to the study of that in China's criminal law. In continental law system, justifiable defence should have the quality of necessity and match. Necessity and match, apparently, is the limit of justifiable defence in continental law system. However, in Common law system, the limits of justifiable defence are stated differently according to different kinds of defences. For example, in American criminal law, justifiable defences are classified into four groups: self-defense, defence of another, defence of property, and defense for law enforcement. Meanwhile it also makes different provisions for the limits of different justifiable defences accordingly.