Marginalized students refer to students who are at school age，under minimum age for employment，but cannot enjoy normal rights. Marginalized students committed crimes have characteristics of young age small，several of crime types，gang crimes，moody crimes，not afraid of punishments，etc. Marginalized students endanger the healthy growth of juveniles，harm to others and the whole society. How to effectively prevent marginalized students from crimes is not only the practical need，also the need of theoretical research.

On the basis of our questionnaire on marginalized students completed in 2013，we compare marginalized students with normal students on committed crimes and behaviors，analyze the risk factors of marginalized students who might to commit crimes，and put forward the countermeasures on preventing marginalized students and the juveniles from committing crimes.