Abstract: In sodium dodecyl benzene sulfonate and Tris-HCl buffer solution, Eu³⁺ and nadifloxacin formed a complex with a fluoresence peak at 618 nm. Based on this, fluorescence spectrometry was applied to the determination of nadifloxacin in drinking water with Eu³⁺ as a fluorescence probe. Linear relationship was found between fluorescence intensity and the concentration of nadifloxacin in the range of 2.0×10^-5-1.0×10^-4mol·L^-1, with detection limit (3s/k) of 4.0×10^-6mol·L^-1. Recovery rates obtained by standard addition method were in the range of 97.5%-101% and RSDs (n=5) were in the range of 1.4%-2.2%.