Abstract: In this paper, estimation of trace silver(I) by catalytic kinetics of the reaction of silver(I) react with α,α'-dipyridyl and potassium ferro-cyanide was studied. It's showed, such catalytic reaction reacted in zero order, and under the conditions supported in this paper, sensibility of this method was 6.5× 10^-4μg/ml and variable coefficient 0.072%. The range of silver estimated was 0-3.5μg/40ml.