Abstract: A new complex ion exchanger,hydrated antimony pentoxide ammonium molybdophosphate,is prepared and its exchanging capacity is studied. The composition and structure of the composite are analyzed by X ray analysis method. This ion exchanger is found to have strong stability and good selectivity for Sr 2+ and Cs +,and it is possible to remove 90 Sr and 137 Cs from waste water by using this new exchanger.