Pyronin Y (PY) has a strong resonance fluorescence in sulfuric acid medium. The characteristics of the resonance fluorescence spectra and the factors affecting the spectra were studied. A catalytic resonance fluorometry method for the determination of hydroquinone was proposed based on the catalytic effect of hydroquinone on the oxidation of PY by potassium bromate. The oxidation of PY resulted in the decrease of the resonance fluorescence intensity. The influences of several variables on the sensitivity were studied. At the optimized conditions, the decrease of the resonance fluorescence intensity was in proportion to the concentration of hydroquinone in the range of 4.42-1.60 x 10(3) microg l(-1), and the detection limit was 1.46 microg l(-1). The proposed method was applied successfully for the determination of trace hydroquinone in environment samples. The relative standard deviation was less than 3.90% and the recoveries were in the range of 95.2-104.0%.