The invention discloses a method for fast expressing the quality stability of polyacrylamide products for oil displacement and application. The method mainly comprises the following steps of firstly, calculating the R value of partial hydrolyzed polyacrylamide products under the condition of different hydrolysis degrees; building a standard curve between the hydrolysis degree and the R value; then, performing quantitative analysis on polymer product ingredients by using an element analysis instrument, and calculating the R value; solving the hydrolysis degree H according to the R value in accordance to a standard curve template; comparing the H with the measured hydrolysis degree H; finally, performing judgment according to the comparison result. The method is used for evaluating the stability of products of ore field use polymers of different batches and achieves the technical implementation effects that the effective control on the quality stability of different kinds of polyacrylamide products for the oil displacement is realized; the ore field polymer displacement is guaranteed; the harvesting rate is improved.