At present, the water storage level in the ThreeGorge Reservoir (TGR) has reached 165 meters. The TGR has changed into a semiclosed water body with slowing flow, and selfpurification ability of water TGR dropped accordingly. The water quality of secondary river becomes one of the direct effects for ecological security in TGR. Based on the analysis of status of eutrophication and happening conditions of secondary river in TGR, ecological engineering technologies for water treatment are discussed in the paper combined with the ecological concepts and routes in the field of river basins at home and abroad.