Recently, serial and heinous crimes committed by high-risk released offenders and psychopathic offenders gave the public a great shock in Korean society. Although these serious and violent crimes do not occupy a large portion of crimes, due to their detrimental effects on the public safety and fear of crime, crimes committed by high risk ex-prisoners need to be addressed. Under the partnership with scholars and practitioners, the current study examined the effective ways of supervising high risk ex-offenders, including electronic monitoring, risk assessment tool, house arrest, a regidential placement of probationers, and high risk ex-offender management system. Regarding electronic monitoring system, using qualitative interview method, empirical research is conducted to assess the effectiveness of electronic monitoring. In addition, legislative issues on electronic monitoring and potential applications and advantages of utilizing home confinement or electronic monitoring in supervising juvenile delinquents are also examined. As the use of house arrest combined with electronic monitoring has expanded in many countries, house arrest as a supplementary factor to enhance supervising function of electronic monitoring is also investigated. Furthermore, a regidential placement of probationers initiated from 2009 is also assessed. As an essential factor for electronic monitoring and effective management of offenders, scientific risk assessment tool is also developed and uated. Last of all, through reviewing other countries’ offender management model, the present study proposed the need of establishing high risk ex-offender management system to reduce recidivism.