A novel coumarin-based fluorescent probe 7-Diethylamino-2-oxo-2H- chromene-3-carboxylic acid quinolin-2-ylmethylene-hydrazide (FKBA) was designed and synthesized to identify Cu2+. FKBA was confirmed by means of IR, EA, MS, 1H NMR, and 13C NMR. The interaction between FKBA and metal ions was investigated via fluorescence spectrophotometry and UV absorption spectrophotometry. The results indicated that FKBA showed excellent selectivity and high sensitivity for Cu2+. Its UV absorption peak was redshift and the maximum UV absorption peaks was also changed when Cu2+ was added. However, under same conditions, it was only a slight change of UV absorption peak after the other metal ions, such as Ag+, Al3+, Ba2+, Ca2+, Cd2+, Co3+, Cr3+, Fe3+, Hg2+, K+, Mn2+, Mg2+, Ni2+, Na+ , Zn2+ and Pb2+were added. The selectivity of FKBA as a chemosensor for Cu2+ was tested by incubating FKBA with a range of environmentally and biologically important metal ions. Fluorescence spectra were notable quenching when Cu2+ was added, with only little interference by other metal ions. Fluorescence spectra of FKBA in the presence of each of different metal ions upon the addition of Cu2+ had the same quenching. Thus, it was notable that FKBA showed good capability of resisting disturbance. The color of FKBA turned from blue to brown upon the addition of Cu2+. The brown of complex restored to the original blue upon the addition of EDTA. The fluorescence intensity regained when EDTA was added, suggesting that fading fluorescence intensity changed due to the formation of KFBA-Cu2+ complex but not any catalytic action of Cu2+. FKBA was not stable and easily hydrolyzed in acidic environment due to their schiff-based structure and part of the FKBA hydrolyzed into other fluorescent substance. Furthermore, the detection limit was 0.13 μmol·L-1 according to the definition by IUPAC (cDL=3Sb/m). FKBA can be used as a fluorescent probe to detect Cu2+ in actual samples.