Background: An enormous amount of liquid radioactive wastes（LRW） was produced by nuclear power plants operation and the reprocessing of spent nuclear fuel.It is necessary to remove 137Cs from LRW to reduce the volumes of waste that require solidification prior to final disposal.Purpose: This paper aimed to study the ion exchange mechanism and uptake behavior for cesium of Ammonium Molybdophosphate（AMP

（NH4）3P（Mo3O10）4.xH2O） in more detail.Methods: Two samples of AMP（AMP-1

AMP-2） were synthesized by different precipitation reactions and they were analyzed by X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FTIR）.The uptake behavior of AMP-2 for Cs+ under different conditions

such as temperature

contact time

competing ions was investigated through batch experiments.Results: The results show that the adsorption reaches equilibrium in 10 min.The adsorption kinetics can be described by the pseudo second-order equation quite well（R2>0.999）.The existence of Na+and K+have negative effects on the uptake of Cs+

while with K+concentration enrichment

the adsorption capacity of Cs+ decreases faster.Conclusions: The results support the theory of isomorphous exchange of Cs ions for ammonium ions.In addition

AMP has the potential to be a very useful ion exchanger in treatment with nuclear waste solution for removal of137Cs.