Abstract: A new spectrophotometric method for the determination of trace nitrite was studied .The method is based on the potassium bromate oxidizing safranine T because of nitrite catalytic agent in phosphoric acid medium.The linear range for the determination is 0～5.6 μg/L NO - 2.The limit of detection is 2.0×10 -8 g/L.The method has been applied to the determination of trace nitrite in purified water.