Abstract: Time travel fictions has enjoyed great popularity on the Internet in recent years and has become the most eyecatching subject matter of public literature.Most time travel fictions integrate history，romance and fantasy，telling stories of romantic love and thus attract many teenagers，especially teenage girls.To some extent，those daydream like stories offer an escape from the stresses in life.But the prevalence of time travel fictions also reflects some problems of teenagers：their illiberal attitudes to life，their disillusion with reality，their unwillingness to “grow up”，and their utilitarian money worship.Those mentalities will have negative effects on teenager mental health and need due attention and proper guidance by both educators and social workers.

Key words: online fiction, youth novel, genre fiction, time travel fictions, teenagers, travel back to the Qing Dynasty, romance