A new method for the determination of seven naphthalenediols in water by liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-MS/MS) was established. The sample was extracted with a C18 cartridge, and then separated by HPLC-MS/MS using a C18 column with methanol aqueous solution as the mobile phase for gradient elution. And the tandem mass spectral acquisition was done in the negative electrospray ionization utilizing multiple reaction monitoring. External standard method was applied for quantization. The result indicated that the limits of determination (LODs) of seven naphthalenediols were ranged from 1.0 ng/L to 3.0 ng/ L (S/N=3), limits of quantification (LOQs) were ranged from 4.0 ng/L to 10 ng/ L (S/N=10); meanwhile, the linear correlation coefficients of seven naphthalenediols were all greater than 0.998 within the irrespective linear ranges. The mean recoveries for well water , tap water and mineral water samples at three spiked concentrations levels of 4.0-50 ng/L were ranged from 81.4% to 112% with RSD of 2.1%-7.8% (n=6). Analysis of blank and fortified samples showed that the relative intensity of the seven naphthalenediols were stable. And there was no matrix interference with these diagnostic ion pairs. Combining with retention time, the method could be used for accurate qualitative analysis.