A cellulose-based material with high adsorption capacity and surface area was developed by selecting appropriate copolymer monomers for structural design. This material was used for selective dye adsorption in wastewater treatment. The copolymer was characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) to investigate its microstructure, structure, thermal stability, and thermal decomposition. We explored the factors affecting dye adsorption, including dye type, adsorption reaction time, initial dye concentration, copolymer dosage, temperature, and the acidity or alkalinity of the reaction environment. The results showed that as the adsorption reaction time increased, the amount of adsorbed Rhodamine B dye gradually increased, and the initial stage (0-20 min) increased rapidly. When the initial dye concentration was 15 mg/L, the adsorption capacity () was at its maximum (3.67 mg/g). In addition, when the amount of copolymer used was 5 mg/10 mL, the adsorption capacity () was the highest (12.37 mg/g). High-temperature conditions were favorable for adsorption, with the maximum adsorption capacity () at 35 °C (13.48 mg/g). The prepared copolymer exhibited significant adsorption performance in acidic environments (pH = 3). The polymer adsorbed with dye was degraded by UV irradiation, avoiding secondary pollution caused by recycling.