Abstract: In the development of bottom water reservoirs, a large part of oil wells were water-flooded by bottom water coning. Whether the additional pressure caused by water injection could prevent the water coning are always the problem that petroleum engineers cares about most. After analyzing of the oil wells production dynamical performance and the geological characteristics of some bottom water reservoir located in northwest China, the numerical simulation technology; streamline simulation technology and virtual tracer simulation technology was adopt to analyze the reasons for inefficacy of water flooding treatment in this reservoir. Through analysis, we found out that most injected water flow to the bottom water area first, and then drive the bottom water flowing to the bottom of oil wells. At the same time, production wells displays obviously bottom water coning characteristic. The flooding path of injected water indicates that, in the bottom water reservoirs, bottom water coning cannot be restrained by maintaining reservoir pressure due to artificial water injection.