Abstract: Ankang C ity and the surrounding areas adjacent to Xunyang Hydropow er S tation reservo ir ta il zone lo ca te on the terrace and the h igh- and low floodpla in of the left bank of the H anjiang R iver. The ground has the typ ical dua listic- structure characteristics. The surface layer of the h igh floodp la in genera lly d istributes relatively th ick artif icial fil.l The bond w ater dynam ic theory and the infiltration flow characteristics of the clay so il are ap plied to de term ine the re lations among the pressurew ater level and the aqu ifer belt of clay layerw ater leve.l In th is research, different submergence cr itical depths are defined by foundation types, depths of bur ia,l fill layer th ick ness of different buildings and the type o f crops of suburbs, etc. the paper calcu lates the g roundw ater Backwa ter V alue and the burial depth o f clay layerw ater- bearing zone in seven d ifferent normal impounded level cond itions to investigate the submergence area and degree. A s a resul,t a reasonable norma l impounded level is determ ined ul t imate ly. Th is result can prov ide a re liab le geological basis for them igration resettlementw ork of th is pro ject reser vo ir area.