Abstract: Internet addiction(IA)is a mental illness emerged in recent years with increasing use of computer and internet. The serious consequences such as mental and physical illness and social function im-pairment caused by IA have attracted extensive attention of the whole society. IA affects human beings at a high prevalence all over the world which has highlighted the importance of prevention and treatment of IA. Although there is still debate about definition of IA, increasing evidences including the result from genetic research, neurobiology study and clinical manifestation show that IA may share the same mechanisms with substance addiction, and be probably classified as behavioral addiction which is represented by pathological gambling. However, since the study on IA is yet on the initial stage and neurobiological research on IA is still limited, more reliable investigations especially neurobiological research remains uppermost in this area.