In order to determine whether dilution water can be used to adjust the weight deviation in cross direction when it is applied to the headbox with perforated rolls,the flow field in the headbox is numerically simulated with the CFD software Fluent.Then,the mixing of two kinds of liquid in the headbox is analyzed by using the Multiphase-Mixture model,and the effects of rotating zone on the flow field are discussed via the rotating reference frame（RRF） approach.Finally,the adjustment effect of dilution water at variable inlet speed and rotation speed of perforated rolls is evaluated.Simulated results show that the adjustment effect of dilution water is linear with the rotation speed of perforated rolls.Experimental results indicate that the addition of dilution water helps to decrease the deviation of the basic weight in cross direction by more than 3 points of percentage.The accordance between the experimental results and the simulated ones proves the applicability of dilution water in the headbox with perforated rolls.