The juvenile justice system of China has undergone drastic changes in the past 30 years or so. In many areas, it has begun to develop and to adjust to be consistent with the world standard. This article examines juvenile delinquency and its reaction—the juvenile justice system in China. It covers the topics of the emergence of a juvenile justice system, age of criminal responsibility, trends in juvenile crime, causes of juvenile delinquency, alternative sanctions, China’s stance toward the United Nations’ Committee on the Rights of the Child, etc. It concludes that with ever-enlarged stratification system, juvenile crime has become a prominent social issue in China. Under the current arrangement, juvenile courts are marginalized and do not have separate funding. Migrant children’s rights are ignored in all big cities. Local initiatives in controlling juvenile crimes are being experimented with in different locations, and some have showed desired effects. Progresses and concerns about juvenile delinquency and its reaction are both rampant.