In many studies, the Numeric Integration(NI) method has been used to calculate the pollutant loads because of its easy to apply. Thus, there have been needed for more accurate pollutant load estimation with a restricted number of water quality samples. And the ESTIMATOR model method has been used to calculate the pollutant loads. However, it requires the user to define the model based on a set of predefined explanatory variables. While similar to the LOADEST model, it is somewhat less flexible. The LOADEST model allows the user to choose between selecting the general form of the regression from among several predefined models and letting the software automatically choose the best model. In this study, stream flow and pollutant loads were analyzed, NI method, ESTIMATOR model method and LOADEST model method were comparatively used to calculate the pollutant loads in the Wolgok-ri watershed, Gangwon Province. Annual loads of T-N and T-P by LOADEST model were 0.49 times and 0.36 times of those by NI method, respectively. And annual loads of T-N and T-P by LOADEST model were 1.45 times and 2.3 times of those by ESTIMATOR model, respectively.