The present study was conducted to investigate whether the supervision of field practicum in social welfare agency have influence on the student's career certainty majoring in social welfare in any way moderated by practicum outcome The participants in this study were 406
students from sixteen four-year universities in Seoul and Gyeonggi province. Collected data were analyzed by frequency analysis to identify the respondents and variables characteristic, path analysis, and mediated effect test. The result revealed that the path from supervision of field training in social welfare organs to the student's career certainty majoring in social welfare was fully mediated by result of training. In other words, achieved result from training is important mediated factor in the relationship between supervision from social welfare organs and student's career certainty majoring in social welfare. Implication of this study is that to provide high quality and systematic supervision through field training is important in order to student's career certainty majoring in social welfare.