The measures of improving flow conditions should be adopt in the over large divergent angle of fore-bay of a pumping station to avoid the side return flow which would worsen the intake conditions of pumps. In the paper, the improvement of flow conditions in the front inflow of fore-bay of the pumping station with setting separation piers is researched by numerical simulation. The 2-D average water depth mathematical model in orthogonal curve-linear coordinate system is used for the numerical simulation. The discreted equations are obtained by finite volume method on staggered grid, and solved by SIMPLEC method. The simulated results show that, the splaying separation piers have good effect on improving the flow conditions in the researched fore-bay with large divergent angle. 