Abstract: A probe base on Rhodamine B derivative F-1(3',6'-bis(diethylamino)-2-phenylspiro [isoindo-line-1,9'-xanthen]-3-one) has been synthesized and developed, which was prepared by condensation reac-tion of Rhodamine B with aniline. Its structure was characterized by 1H NMR, 13C NMR and HRMS. It was found that after the Fe3+ added, the probe system changed from colorless to purple and the fluores-cence intensity was significantly enhanced, while other metal ions (Na+, K+, Ca2+, Mg2+, Zn2+, Hg2+, Co2+, Cd2+, Ni2+, Cu2+, Mn2+, Ag+, Pb2+, Cr3+, Fe2+) were not disturbed. By measuring the ion selectivity, ion competi-tiveness, concentration gradient, Job curve, and the effect of pH on the fluorescence intensity of probe compound F-1, we found that probe compound F-1 presents a good linear relationship in pH=5-7 (2.0×10-6~1.8×10-5 mol/L), and has the potential of qualitative and quantitative detection of trace Fe3+ in bio-logical organisms and environment.