The pectin/AMP-Zn microsphere was prepared by embedding ammonium phosphomolybdate (AMP) in pectin by electrostatic-injecting device using gel-sol method and Zn2+ as crosslinking agent, which was used in the removal of Cs+ in radioactive waste water. The effects on adsorption cesium were systematically investigated, including pH, dosage, contact time, initial concentration of Cs+, temperature and coexisting ions. The adsorption mechanism was analyzed by means of SEM, FTIR and XPS. Furthermore, the results showed that the pectin/AMP-Zn microspheres could be applied in a range of pH=3~11. Therefore, the adsorbent had good acid and alkali resistance. The adsorption capacity of adsorbent was 41.837 mg/g under the condition of pH=5, initial mass concentration of 120 mg/L and adsorption dose of 0.05 g. The presence of competing ions (K+, Na+, Li+, Ca2+ and Mg2+) had no effect on the cesium adsorption, which indicated pectin/AMP-Zn microspheres had high selectivity. Thermodynamic and kinetic studies exhibited that it was fitted well with Freundlich model and pseudo-second-order kinetic model, respectively. Besides, the process that the adsorption of cesium onto pectin/AMP-Zn microspheres was a spontaneous exothermic process. In addition, above-mentioned characterization methods confirmed that the adsorption mechanism was ion exchange reaction between NH4+ and Cs+.