Water is an essential ingredient of life. Currently, this natural resource has been under pressure from the socio-economic development. This paper presents the application of remote sensing technology to monitor organic pollutants in water from Hoa An bridge to the confluence of the Saigon and Dong Nai River. The river water indicator was surveyed as Dissolved Oxygen (DO) and was calculated via spectral channels of Landsat 8 at the time of January 21, 2014. Research methods was approached in the direction of: Qualitative simulation from the spectral characteristics, and quantitative simulation based on regression analysis. The results showed that the concentration of the observed indicator DO had a linear correlation with the ratio based on green band B3 and red band B4 of Landsat 8 image. From the regression, this study established the spatial distribution maps to simulate organic pollutants in rive water of the studied area. The classification system was built according to the standards of QCVN08:2008/BTNMT. The study results shows that the application of remote sensing monitoring river water quality is a good support tool for environmental management purposes, to help policy-makers to see and have better decisions for the local socio-economic development.