Morality has always been the focus in psychology and philosophy study. In psychology researches, many researchers have been done some contributions. Meanwhile, lots of psychological theories have been proposed to explain the mechanism of human morality. We can find that a lot of people have accurate moral judgments, but they have some immoral behaviors. Some researchers started to figure out the question why moral people did immoral behavior. Recently, lots of studies indicated that moral emotion can play important role in the moral behaviors. Otherwise, some psychologists explored the new psychological mechanism of moral behaviors. So, Bandura’s social cognition theory became the base of moral study, again. Moral disengagement, a cognitive process, can make self-control fail to inhibit the immoral decision and the immoral behavior. In Bandura’s explain of the concept and process of moral disengagement, there are eight mechanisms (moral justification, euphemistic labeling, advantageous comparison, displacement of responsibility, diffusion of responsibility, distorting consequences, attribution of blame, dehumanization). Our society and educational system ugly want to acknowledge why some adolescents did immoral behaviors. And our parents need to comprehend how to deal with the immoral behaviors and the deviant adolescents. So analyzing the immoral behaviors on internet is very important. This study wanted to build a model about the relationship between individual trait, family factors and adolescent immoral behavior. We also focus the role of moral identity, social responsibility, moral disengagement on the relationship between parenting style and immoral behaviors on line. The study wants to display the influence of parenting style, social responsibility, moral identity and moral disengagement on the adolescent immoral behavior on line. There are 764 participants attending this research. Completing five questionnaires, data are analyzed through structural equation model. The final model indicated that there is no direct path between parenting style and immoral behavior. And there is a direct relationship between moral identity and immoral behavior. Moral disengagement can mediate the relationship between moral identity (and responsibility) and immoral behavior. Meanwhile, moral identity and social responsibility can mediate the relationship between moral disengagement and parenting style. The results indicated the magnificent function of the moral disengagement on the relationship between parenting style and the immoral behaviors. Specially speaking, the pathway involved the moral disengagement can explain almost the effect of parenting style on the adolescent immoral behaviors on line. Finally, the implications and the inferences are discussed in the article. Our study indicated that we need more moral practices education rather than moral principles education. Meanwhile, our school and teacher should pay more attention on the absurd explanation to immoral behavior of adolescents. We should pay more attention on the moral identity that shows the importance of moral trait in self. Although our research show that reject parenting didn’t predict adolescent immoral behavior, the parenting style can influence immoral behavior indirectly (through the mediation effect).So parents need diminish reject and increase warmth and response to children.