Aiming at the undesirable flow patterns in the discharging flow of a sluice-pump station, double sills were applied in the downstream for rectification. The rectification effects and the hydraulic characteristics were explored based on RNG k-ε turbulence model and VOF method. The calculation results were verified by a physical model experiment. The results show that the sill forces the discharge flow to move laterally along the sill and form a vortex which can significantly improve the flow bias, backflow and oblique jump. The double sills can effectively reduce the wave motion, the recirculation zone, and improve the uniformity of velocity. The velocity non-uniformity coefficient decreases with the increase of the Fr number at the downstream outlets, and decreases first and then increases with the increase of the relative height h2/b and relative spacing d2/b of the second sill. By qualitatively and quantitatively comparing the mathematical and physical model results, it is found that the water surface curve and the velocity distribution are well consistent with each other, indicating that the numerical simulation of the turbulence model applied is reliable.