The purpose of this study is to introduce a rural development project utilized Participatory Rural Appraisal(PRA), which has been widely developed and applied as an approach and methods for participatory rural development since 1990’s. In the ODA project titled as “Happiness Program”, a comprehensive community development program designed and conducted by KOICA for underprivileged ethnic minorities in Lao Cai province, Vietnam, the villagers were able to analyse the realities of their situations, to plan, to act, and to monitor and evaluate their actions for improvement through all the processes of PRA utilization. Apart from the successful implementation of participatory rural development activities, this project also made a contribution to extending our knowledge about PRA by presenting the monitoring and evaluation system built for the project and the impact analyzed by the system such as increase in villagers’ annual income, expansion of infrastructure, capacity development and etc.