Abstract: In order to solve the problems of poor swelling property of sodium alginate microspheres, large mass transfer resistance between adsorbent and adsorbate, and few adsorption sites after drying, a thermal-responsive interpenetrating polymer network hydrogel microspheres were prepared by free radical polymerization and ionic crosslinking, and modified by "pore forming+phosphate group functionalization" (P/PF@TR-IPN). The effects of initial uranium concentration, ZnO content, dosage, pH value, temperature, interfering ions and adsorption time on U(VI) adsorption were studied by single factor experiment, and its regeneration performance was explored. When the initial concentration of U(VI) is 10 mg∙L⁻¹, the pH value is 4, the dosage of P/PF@TR-IPN is 0.4 g∙L⁻¹, and the temperature is 25℃, the removal rate of U (VI) by P/PF@TR-IPN is 94.8% within 6 h, which is 18.5% and 30.03% higher than that of PF@TR-IPN and TR-IPN, respectively. With the increase of temperature from 20 ℃ to 50℃, the swelling rate of temperature-sensitive microspheres P/PF@TR-IPN decreases from 6.98% to 5.14%. The BET specific surface area of P/PF@TR-IPN is 28.5 times larger than that of TR-IPN. When pH value is 4 and the temperature is 30℃ and 20℃, the maximum adsorption capacity of P/PF@TR-IPN for U(VI) is 76.99 mg∙g⁻¹ and 85.62 mg∙g⁻¹, respectively. The removal of U(VI) follows the monolayer chemical adsorption process, and the pseudo-second-order kinetic model and Langmuir model can better fit the adsorption process of U(VI) by P/PF@TR-IPN. The results show that the 3D porous structure and the formation of new active adsorption sites of phosphate groups are the two main factors for the increase of U(VI) removal efficiency, the main mechanisms of U(VI) removal by P/PF@TR-IPN include the chemical adsorption of phosphate group coprecipitation and the surface complexation of sodium alginate oxygen-containing functional groups.