Abstract: The application of nitrous oxide-ethyne flame atomic absorption spectrum to research of Iron content measurement in copper-silver alloy of cadmium nickel battery is studied. This paper introduces the optimum measuring conditions for Iron content and potency in which a fine liner range presents. The method has the advantages of high sensitivity, less interference and good in selectivity and reappearance. The relative standard deviations are all less than 1.0% (n=10) in ten sample measures, and the standard recovery is in the range of 97.0%～99.0%.