It is required to estimate Nonpoint Source (NPS) pollutant loadings and to evaluate emission characteristics of NPS in order to protect and manage eutrophication in a stream. Thus, the purpose of this study is to 1) calculate total pollutant loadings and pollutant loadings by baseflow from the stream using Numeric Intergration (NI), ESTIMATOR, and LOADEST, and to 2) give a guideline regarding the most appropriate model for estimating pollutant loadings through the comparison of NI, ESTIMATOR, and LOADEST. As a result of this study, of total pollutant loadings from the stream, pollutant loadings by baseflow ranges from 54 to 85 %. Therefore, because the result of this study shows that pollutant loadings by baseflow are bigger than that by streamflow, it is very necessary for the efficient management of pollutant loadings by baseflow.