Water affair disputes of interprovincial rivers in Yangtze River Valley are characterized by complex, sensitivity, multiformity and s udden occurrence. For designing a planning in advance and strengthening supervision to effectively avoid water-affair disputes, a Yangtze River Valley interprovincial rivers GIS has been established on the basis of both the 1∶250 000 and 1∶50 000 river vector database of Yangtze River Valley. This system adopts a three-layer distributed architecture, in which three kinds of technologies——GIS, WEB and database are fused. It possesses better foreseeable capacity and higher practicality, such as a long-distance visit of database. Through trial operations for a longer time, it is in good working order.