Three-dimensional fluorescence spectroscopy is a new and effective chemical analysis method and is employed in water environment more and more widely. But the utilization is limited by the bottleneck, i.e. shortage of fluorescence data of contaminants in aqueous solution. This paper presents the three-dimensional fluorescence properties of a toxic contaminant, sodium butyl naphthalene sulfonate, in aqueous solution. There existed four peaks at about λex/em=230/340, 280/340, 225/650 and 280/650 nm respectively. The intensity of all the peaks except the peak at 225/650 nm increased as the concentration augmented, while the intensity of peak at 225/650 nm increased as the concentration augmented when the concentration was less than 0.5 mg·L-1, and decreased as the concentration augmented when the concentration was greater than 0.5 mg·L-1. The pH would lead to the variation in the fluorescence intensity vary rather than to change the peak location. The fluorescence intensities were stable when pH was in the range of 2～10. The study indicates that it is feasible to measure sodium butyl naphthalene sulfonate directly with the fluorescence intensity at 280/340 nm. The linear range is between 0 and 0.033 3 mg·L-1. This simple and rapid method could provide reliable results without complex pretreatment.