This study is to investigate the temporal and spatial variations of the BOD pollutant load at stream flowing into the Masan bay. We investigated at seventeen sampling points from 2016 to 2021 and calculated the BOD pollutant load. The LOADEST model was used as a tool to calculate daily load, the load was analyzed by day and month, and the contribution rate by season was calculated. The average R2 value for all streams was 0.707, which was within the Good range, and regression equations 1, 7, and 9 were derived as appropriate regression equations. For streams that have been dried or are small in size, regression equation 1 was found to be the appropriate regression equation, and for other streams, regression equations 7 and 9 were shown to be the appropriate regression equation. The periods of high pollution load were in the order of July, August, June, and May, and the order showing the highest contribution rate on average was Nam stream, Daejang stream, and Hoewon stream.