Abstract: In the FAAS determination of microamounts of rubidium in chloride bittern,interferences of co-existing ions,including K+,Na+,Ca2+ and Mg2+,were tested,and on the basis of the results obtained,the analytical conditions for FAAS determination of rubidium given in literature were modified.It was found that when definite amounts of the co-existing ions very close to the amounts present in the sample were added to the testing solutions in the preparation of standard curve of rubidium,their interferences were eliminated by compensation.Thus,rebidium in bittern was determined directly without any pretreatment.The proposed method was applied to determine rubidium in 2 known bittern samples,giving results in consistency with the known values,and giving values of recovery in the range of 92%-108%.