3-Phenyl-pyrrolo[2,1,5-cd]indolizine-1-carboxylic acid(2-hydroxy-benzylidene)-hydrazide(6) was synthesized and used as fluorescent sensors for Cu2+ ion. The structure of the compound 6 was determined by IR, 1H NMR, MS and elemental analysis and their UV and fluorescence spectra were measured. The influences of ten metal ions such as Cu2+, Zn2+, Ni2+, Co2+, Al3+, Cr3+, Mn2+, Na+, Sn2+ and Ca2+ on their fluorescence properties were studied. Spectroscopic studies revealed that the compound 6 had rather strong affinity toward Cu2+. The specificity of the probe 6 toward Cu2+ was determined. Nearly no fluorescence intensity changes were observed in emission spectra with Zn2+, Ca2+, Na+, K+, Cr3+, Sn2+, Al3+ but Ni2+ and Co2+. However, under identical conditions, the results showed fluorescence quenching with Cu2+. So we have developed a new fluorescent sensor 6. It shows high sensitivity and selectivity toward Cu2+ in DMSO.