A simple and efficient fluorescent chemosensor for Al(3+) is reported in the paper. The chemosensor is obtained by dehydration reaction of 2-hydroxy-1-naphthaldehyde and 2-aminophenol. The chemosensor has high selectivity and sensitivity for Al(3+) and displays fluorescence "off-on" switch signal. The detection limit of the chemosensor for Al(3+) can reach 1.0×10(-7) M in DMSO/H2O (1:9, v/v) solution. The mass spectra and Job's plot analysis confirm the 1:1 stoichiometry between chemosensor and Al(3+). Potential utilization of the probe as an intracellular sensor of Al(3+) in human cancer (HiSa) cells is also examined by confocal fluorescence microscopy.