Adsorption behavior of Sr(Ⅱ) ions was investigated using gel adsorbents based on three types of polysaccharide derivates: carboxymethylated cellulose (CMC), carboxymethylated chitosan (CMCts) and hydroxypropyl methylcellulose phthalate (HPMCP). Maximum adsorption capacities were reached in about 0.5 h for CMCts, 1 h for CMC, and 2 h for HPMCP. The adsorption capacity increased with increasing pH, and decreasing ionic strength. The maximum adsorption capacity of Sr(Ⅱ) ions into CMC, CMCts and HPMCP gels at 25 ◦C were 108.7, 99.0, and 83.3 mg/g gel, respectively, based on the Langmuir isotherms. XPS analysis indicates that Sr(Ⅱ) ions are adsorbed into the three adsorbents according to the ion-exchange mechanism. Desorption of Sr(Ⅱ) ions could be carried on by immersing the adsorbents in the solutions with low pH or high ionic strength, or heating the adsorbents in the moist hot environment.