A series of fluorescent sensors based on 8-hydroxyquinoline dansylate as core and dendritic PAMAM as shell were synthesized. Their fluorescence characteristic and fluorescent sensing behavior toward metal ions were studied in water/methanol (1: 1, v/v). The sensors exhibit good selectivity and sensitivity for Fe(3+) ion and to some extent for Cr(3+) ion. The third generation dendrimer has the better sensitivity than the first and second generations.