This paper probes the severe social problem,that is,the crimes of juveniles maintain at a high rate in China.It penetrates into new trends of such crimes and their causes.With guidance of Fourth Plenum of the 16th Central Committee of the CPC,it illustrates that precaution against the crimes of juveniles is a complex systematic project.Families,schools,and society should pay a special concern,act in close coordination and make concerted efforts to guard against it.