Abstract: According to classified assessment thought and principle, this article explores assessment system about cascade hydropower development in main stream of Jinsha River effecting on ecology geology environment with four big kinds of subsystems such as assessment subsystem about slope (bank slope) stability, assessment subsystem about soil and water loss and reservoir sedimentation, assessment subsystem about ecological environment evolution and subsystem about influence of social economy development as its trunk, initially establishes four big kind of assessment index system and assessment method, and then separately carries on assessment on it, finally carries on the comprehensive analysis assessment to the ecology geology environmental effect of cascade hydropower development in main stream of Jinsha River.