Abstract: Although the criminal law and the civil law are different in the standard, the goal, the adjustment method and so on, they cannot be treated simply. The relationship between them is embodied in the understanding of "division" and "co-operation". On the one hand, "division" is the distinction of the social harmfulness. The criminal law regulates the behavior which is seriously harmful to the society, and the tort is regulated by the civil law. Social harmfulness is not unchangeable, but it will change with the change of social cognition. Therefore, the boundary between the criminal law and the civil law should be adjusted accordingly. On the other hand, "co-operation" means that both of them are indispensable to the handling of harmful incidents. In dealing with the relationship between the criminal law and the civil law, criminal law should be alert to the priority of thinking, abide by the modesty of criminal law, we should also pay attention to the fact that the civil judgment cannot be replaced by the criminal judgment and the behavior should be determined by using the norms of the civil law and the criminal law.