Abstract: Aiming at the problem of PTA slurry preparation in PET plant, this paper considers the modeling of esterification reaction procedure, and proposes a cascade ratio control strategy, in which the density of PTA slurry and the amount of EG mixture are chosen as control variables. Besides, temperature variable is utilized to modify the PTA slurry density and molar formula. The proposed method in this paper may benefit the improvement of the polyester production process control and the quality of polyester products.