Abstract: A method of flow injection ion exchange separation followed by flame atomic absorption spectrometry for the speciation analysis of iron was studied in this paper.Iron(Ⅲ) in sample solution was masked by addition of NH4F and Fe(Ⅱ) was adsorbed on the micro column packed with 732# cation exchange resin.The adsorbed Fe(Ⅱ) was then eluted with 6 mol·L-1 HCl solution.Fe(Ⅲ) and Fe(Ⅱ) were successively determined by flame atomic absorption spectrometry.Detection limits of this method were found as 0.07 mg·L-1 for Fe(Ⅲ) and 0.01 mg·L-1 for Fe(Ⅱ),and RSD′s (n=7) of 3.37% for Fe(Ⅲ) and 1.95% for Fe(Ⅱ).Using the proposed method,about 5 samples can be analyzed in an hour.