In recent years with the continuous development of new media technology， idols represented by stars have a far greater influence on young fans – fan group – than family and school education could have. Therefore， learning relevant characteristics of fan group is helpful for improving the effectiveness of youth education. We find that fan group identification has the following core characteristics： projection of an ideal self， a safety valve to release anxiety， a haven to satisfy the sense of belonging， and so on. Fan group also has two positive social effects： imagined communities and incubator for public welfare. At the same time， fan group has also exposed the following problems： spreading of cyber violence and frequent cases of infringement and illegality； more occurrences of extremist behavior and interruptions of public order； manipulations by capital and induced fans consumptions. To reduce the negative impact and promote the healthy growth of the youth， the following measures are proposed： to guide youth to cultivate correct values and improve their qualities； to give more care to youth and increase the attractions of offline life； to strengthen the supervision over capital and punish illegal acts.