The work aims to prepare a fluorescent polymer hydrogel, improve the mechanical stability, moisture retention, and multi-environment stability of the hydrogel and enable the test of concealing code information inside the hydrogel, so as to increase the adaptability of the hydrogel in harsh environments and explore its application prospects in information storage and anti-counterfeiting. Sodium carboxymethyl cellulose (CMC) was dissolved in a water/dimethyl sulfoxide (DMSO) system at 70 ℃. On this basis, acrylic acid, acrylamide, and 2-methoxy-ethyl acrylate were added, and specified designs were then printed using fluorescein solution. Finally, the mixed solution was cured by ultraviolet light. The mechanical and antifreeze properties were characterized by a universal test tensile machine and a differential scanning calorimeter. Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscopy (SEM) were used to describe the internal material and morphology. The outcomes demonstrated that the water/DMSO system might enhance the gel's mechanical characteristics at low temperature. And the generated transparent hydrogel would swell when submerged in water and regain its clarity when immersed in DMSO solution. So it could be utilized to conceal and encrypt the fluorescence data. In conclusion, the fluorescence pattern could be concealed and the information could be prevented from being visible under ultraviolet light when swelling according to the microphase separation in poor solvent and swelling phenomenon in organic solvent of hydrogels. So hydrogels have a wide range of potential applications in information encryption.