The highly cross-linked PDMA star polymer (PDMA-b-PEGDMA) was successfully synthesized by group transfer polymerization (GTP) using 2-(N,N-dimethylamino)ethyl methacrylate (DMA) and cross-linking agent ethylene glycol dimethacrylate (EGDMA) monomers. Highly cross-linked polymer as a huge molecule has many functional groups. Thanks to these properties, dye adsorption performance of this kind of polymer was investigated. Sunset yellow FCF (SY) dye was used to determine whether the polymer showed adsorption properties. The effect of solution pH, dye concentration change and adsorbent amount on adsorption were investigated and the most effective adsorption conditions were determined for polymer. According to these parameters, the reaction rate constants in the dye adsorption of highly cross-linked polymer and the thermodynamic parameters (Delta H degrees, Delta G degrees and Delta S degrees) of the adsorption were calculated. The reaction was spontaneous (Delta G degrees < 0) at all temperatures (20 degrees C, 35 degrees C, and 50 degrees C). Kinetic of adsorption of SY dye onto polymer was studied, as well as its adsorption isotherm. At the last stage of the study, recovery of the polymer was carried out. The polymer was recovered using the dissolution-precipitation method. Adsorption studies were performed using UV-Vis spectrophotometer. The characterizations of the synthesized highly cross-linked star polymer and the recovered polymer were carried out using proton NMR (H-1 NMR) spectroscopy and gel permeation chromatography (GPC).