Abstract: In this paper the concept of target transfer function array is presented.By using this concept expected performance index is expressed.And then a multivariable PID control frequency domain design technique is introduced by parameter optimizationapproach.In a closed loop system designed by this technique,the frequency responceis almost same as the target array,the output transient performance is quite satisfactory,and no steady state error.This technique is used in paper-making process forthe weight and moisture control system design and an expected result is given.