Abstract: Ammonium phosphomolybdate/polyacrylic acid composite adsorbent(AMP-PA) was synthesized. The AMP-PA was characterized by FTIR and XRD. The effect of contact time, nitrate acid concentration, Cs⁺ concentration and co-existing cations was studied by batch experiments. The static experiment results show that the equilibrium of cesium adsorption at AMP-PA is about 5 hours. The concentration of HNO₃ has little effect on the adsorption amount of cesium in the range of 0-3.0 mol/L. The adsorption process can be described by Langmuir equation, and the calculated adsorption capacity reaches 4.7 mg/g. The desorption rate is about 70% using 3.0 mol/L NH₄Cl+1.0 mol/L HNO₃. Cesium ions can be selectively adsorbed in the presence of foreign cations. The column operations show that cesium adsorption capacity on AMP-PA is 4.32 mg/g, and the desorption rate is about 50.4%. Cesium can be selectively extracted in the presence of Na⁺, K⁺, Sr²⁺, Co²⁺, Fe³⁺, Zn²⁺, and Ca²⁺. In the leaching solution of cesium, the concentration of Co²⁺ is lower than detection concentration. The concentration of Fe³⁺ is the highest among the foreign cations, which separation factor is about 3, and is four orders of magnitude lower than the initial concentration.