The polluted water, mixture of chemicals and dyes, discharged by various textile and paper industries, is a serious problem for the environment, peculiarly the water. Dyes are stable to light, heat and oxidizing agents and are usually biologically non-degradable, which makes them complicated environmental pollutants. To examine the removal of dye from water, a three-dimensional poly (2-hydroxyethyl methacrylate) (PHEMA) and eosin Y were used, respectively, as a dye retention support and pollutant. The study of the interaction between dye and a hydrophilic polymer networks by the conformational modeling using computer software represents the goal of the present work. Both the swelling and ultraviolet-visible spectrophotometry studies show that the pollutant was well retained by the porous polymer network PHEMA. The conformational study of the system composed of polymer network/dye shows that the interaction of the oxygen (O) and bromine (Br) of eosin Y with the hydrogen (H) of the PHEMA depends on the polymer porosity that was varied by the cross-linking rate of the three-dimensional polymer networks. The results obtained by this work can be applied to improve the retention efficiency of such material for use in wastewater application.