A new fluorescence quenching method for the determination of trace mercury has been established.This method is based on the facts that 2,3-dihydro-9,10-dihydroxy-1,4-anthraquinone（R）can emit strong and stable fluorescence in HCl solution with α,α’-dipyridine,and α,α’-dipyridine can activate Hg2+ catalyzing the reaction of H2O2oxidizing R to non-fluorescence complex which cause the fluorescence quenching.The regression equation of working curve can be expressed as △If = 10.19 + 199.9 C Hg2+（ng/mL）（r = 0.9994,n =5）.The limit detection（LD） is 7.2 × 10-13g Hg2+/mL（n=11）.The sample containing 0.0040 and 0.40ng/ml Hg2+ are repeatedly determined for 11 times.RSD are 2.2% and 3.4% respectively.R is synthesized in this paper.Meanwhile,the structure is determined by 1H-NMR,IR,MS and UV-Vis spectroscopy.
