Abstract: A method for the determination of tin in antimory trioxide by hydride generationatomic fluorescence spectrometry was proposed, which base on the Sn (Ⅱ) reduced to SnH4 by potassium borohydride in the media of 10% hydrochloric acid. At 500℃ and in the existence of ammonium chloride and zinc, antimony was transformed to volatile antimony trichloride and them removed. Tin and zinc was formed to zinctin alloy and remained in the residue, so as to eliminate the interference of antimony on the determination of tin. The detection limit of the method for tin is 0.20 mg/kg and recovery is 91.0％～104.5% with precision of 3.73%RSD (n=7).