This paper proposed a method for studying environmental impacts of a super-large reservoir by using remote sensing method. The method consists of three subsystems corroborating each other. A case study was conducted on Miyun reservoir area of Beijing. For which various information extraction techniques were employed and results then assessed. In combination with analysing on ground-true data

the governing factors relating to the regional environment of the reservoir were thoroughly evaluated on a qualitative and partially quantitative base. A conclusion is drawn that Miyun reservoir has a possitive effect on and an improvement function for its surrounding ecological environment.The paper revealed a broad future for using remore sensing technique in analysing impacts of super-large reservoirs. At the meantime

some limitations and its possible solutions of using such a technique were also discussed.