Gold nanoclusters were synthesized based on oxidized glutathione(GSSG) with a mean diameter of 2.9 nm.The fluorescence of GSSG-Au NCs was strongly quenched when Fe3+ ions were present.The sensor was used to detelt Fe3+ ions has a wide linear range of 0.1-30 μmol/L,a high sensitivity of 0.03 μmol/L and a good selectivity.The method described was successfully applied in real sample(tap water,lake water and river water samples) determination.