Abstract: The current fauna,standing crop (density and biomass) and distribution,ect.on phytoplankton in the upper water of the Yinluan Project are investigated and studied.Based on the present study and referring to the historic investigated data and the information from the studies on allied domestic water bodies,an ecological and environmental status of the investigated area is assessed and evaluated.The research result suggests that the water quality of the area can be delimited to mesotrophic type and that the water quality is good.However,the net-box fish farming in Panjiakou and Daheiting reservoirs in the downstream has somewhat affected local waters,and the resulted eutrophication trend should be paid sufficient attention to.