Abstract: According to the actual process parameters, the effect of different header inlets and flow deflectors on water flow distribution in the quenching machine was using the software FEM ANSYS. The results obtained through numerical simulation indicated that the header with middle water inlet can form the central convex water distribution to a certain extent along the deflector width so as to acquire the reasonable water flow distribution easier than terminal inlet. The damping effect due to flow deflectors in header can significantly improve the sprinkled flowrate distribution. Taking the slot nozzle we developed as an example, the flow properties of water jet in slot were analyzed. Simulation results revealed that the flowrate distribution of water jets from the slot nozzles is quite uniform with small turbulence, thus benefiting the homogeneity during cooling the plates being quenched. The water-sprinkled cooling system has been applied successfully to the roller quenching machine with its favorable performance proved.