MOF-5-NH2 was prepared by using 2-aminoterephthalic acid and zinc nitrate hexahydrate at room temperature. A fluorescent composite MOF-5-NH2@C was prepared by encapsulating 7-N,N""-((7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)hydrazinecarbothiohydrazide (C) into the pores of MOF-5-NH2 by impregnation method. The structure and composition of MOF-5-NH2 and MOF-5-NH2@C were characterized by SEM, XRD, FT-IR and XPS. The fluorescence recognition properties of MOF-5-NH2@C for 15 common metal cations (K+, Ca2+, Na+, Mg2+, Fe3+, Co2+, Cu2+, Zn2+, Ag+, Cd2+, Pb2+, Cd2+, Hg2+, Ni2+, Al3+) were investigated. The results show that in ethanol, MOF-5-NH2@C has a fluorescence enhancement of 162 times in the presence of Al3+, and the detection limit is 0.328 μmol/L. It has good anti-interference and naked-eye recognition ability, and can detect Al3+ in actual water samples.