As South Korea gradually enters into the multicultural society, the crimes committed by expatriates are considered as a new threat of public security. Against this context, this study analyzes the characteristics and causes of Chinese immigrants" crimes focusing on Guro district in Seoul. We used the Korean Information System of Criminal Justice Services for the analysis of the status and characteristics of expatriates" crime. According to regression analysis of the data, there is no statistically significance in the violent crime rate between the Chinese expatriates and Koreans. However, Guro District densely populated with the Chinese shows the higher rate of murder and assault. Hence, the concentration, not the foreigner itself, can be one of causes of the violent crime. Moreover, our interview with the police and residents reveals that most violent crimes accidently happen under the weakened informal social control. Therefore, establishing the immediate response system to physical violence can help prevent more serious crimes.