The objective of this research was to study the adsorption and photodegradation of Malachite Green (MG) dye by using poly(2-hydroxyethylmethacrylate) (PHEMA) hydrogel and nanocomposite TiO2PHEMA hydrogel. The nanocomposite gels were characterized by FT-IR and XRD. The adsorption of MG dye was examined through monitoring UV-Vis absorption. The kinetic study indicated that the adsorption follows the first order kinetics. The adsorption equilibrium data fit well to the Langmuir isotherm model. The photodegradation of MG dye was examined using TLC UV lamp and medium pressure Hg lamp. It was determined that the unloaded composite gels adsorb MG dye from the solution at the beginning while under the photochemical condition. The dye in the gel was eventually photodegraded, indicating that the photodegradation process is still effective to dyes in the gel system. The composite gels containing anatase/rutile mixed phase titania are much better photocatalysts than those containing pure phase titania (either rutile or anatse).