Nowadays the phenomenon of the internet addiction disorder （IAD） is prevalent in the teen-ages. In this paper we analyze three aspects of its reason: network game is not the origin of IAD;the external cause of IAD（educating system

home education and society）;the internal cause of IAD （characteristic of teen-ages）. “Stop”is not efficient but harmful. It is the most important for the addict’s parents to lead their children by adopting effective approach. They should love their children indeed. All in all we ought to insist on the principle

“prevention is on the top priority

treating both the incidental and fundamental aspects simultaneously”.