Process change and modification, which are caused by process failure, equipment life cycle and economic environment, have been generated in the chemical plants. And the MOC (management of change) base on the reasonable process safety technology such as change judgment, hazard identification by accurate technical references and risk assessment. But it is difficult to carry out the MOC because of lack of experience, shortage of knowledge and none of process safety specialists. In this study, the MOC system which could make enhancement of safety by finding and complementing weakness of MOC in chemical facilities was developed. This developed MOC system based on QRA was recommended the obvious standard for decision-making process, MOC procedure based on risk assessment and risk estimation of the process modification. The study based on the above way sought the enhancement of safety by performing Risk Based MOC for chemical plants.