Abstract: Three-dimensional seepage model of bottom water reservoir is established,which analyzes the flow variation regularity of bottom water reservoir pressure,quantity of flow and accumulative flow discharge under different water body outer boundary conditions.The results indicate the pressure and flow characteristics of bottom water reservoir can be divided into three stages.On double logarithmic coordinate axis,the early dimensionless pressure-drop and the time present a linear relationship,when the pressure drop increases rapidly,the flow rate and accumulative flow rate rises rapidly.In transition period,the pressure drop rises slowly,the decrease of flow rate slows down,and the accumulative flow rate rises slowly.As for the infinite outer boundary,the descent speed of reservoir pressure is zero and the flow rate declines gradually.As for the constant pressure outer boundary,the descent speed of reservoir pressure is zero and the flow rate keeps stable.As for the closed outer boundary,the reservoir pressure drops faster and faster and the flow rate drops.