The invention discloses a method for quickly determining the content of barium in a nickel salt solution. In 0.12 mol/L of hydrochloric acid medium, tribromoarsenazo and barium can form a stable purple complex, and according to the spectrophotometric analysis principle, accurate determination of the content of the barium in a nickel chloride solution or a nickel nitrate solution is completed. Themethod comprises the specific steps that 5.0 mL of 0.6 mol/L hydrochloric acid solution and 2.0 mL of 50 g/L ascorbic acid solution are added into the pretreated nickel chloride or nickel nitrate solution in a 25 mL volumetric flask in sequence and mixed evenly, then 5.0 mL of 1g/L tribromoarsenazo solution is added, and the volume is metered; with the reagent blank as a reference, the absorbancyis measured at the wave length of 620 nm, and according to the absorbancy value, the content of the barium in the to-be-measured solution is obtained on a working curve. By means of the method, the content of the barium is within the range from 0 microgram/25 mL to 50 micrograms/25 mL and accords with the Beer's law, and the apparent molar absorption coefficient epsilon is 4.64*10<4>Lmol<-1>cm<-1>; the recycling rate is 95-103%, RSD is smaller than 10%, the method is stable, reliable, quick and simple, and requirements for quick analysis of the barium in the nickel chloride and nickel nitrateproduction process can be met.