The purpose of this study is to enhance control capability of river water quality and environment by developing algal bloom monitoring technology using Unmanned Aerial Vehicle. The study acquired remote sensing data using UAV on the midstream area of Nakdong River, one of four major rivers in South Korea. The study also conducted water quality analysis and spectral reflectance measuring in the field to identify emergence aspect of phytoplankton in waters of the river and to induce algal bloom detection index equation through wavelength mixing of sensors. The result showed that the result values of algal bloom detection obtained from wavelength band mixing had strong positive correlation with algae standing crops. Besides, the results of analyzing spatial distribution of algal bloom of the overall investigated water area showed that the area of 0.22 km²~0.26km² had severity equivalent to the level of warning (5,000~1,000,000cells/mL) in 2015 criteria for issuing algae warnings. It is expected that when this remote water quality and pollution monitoring technology is applied in the field, it would be able to improve capabilities to deal with the river water quality and pollution at the early stage.