Abstract: Cold-Atomic fluorescence spectrometry method is used to analyze Mercury(Hg) in water.The instrumental parameters and the conditions of measurement such as the concentration of hydrochloric acid and potassium borohydride are investigated in detail.Under the optimum conditions,Hg has good linearity in the ranges of 0~10.00 μg/L with correlation coefficients above 0.9995.The detection limit is 0.002 9 μg/L,and RSD is less than 1.98%.The recovery obtained by standard addition method is in the ranges of 90.0%~99.6%.The method is simple,rapid,less noise,high sensitivity and reproducible.The method has been applied to determination of trace amounts of Hg in water.