The invention discloses a composition for maintaining the stability of the residual polymer in polymer flooding produced water, wherein the composition comprises, by mass concentration, 50-200 mg/L aninhibitor for emulsified oil-induced influence, 100-150 mg/L an inhibitor for solid suspended matter-induced influence, and 50-100 mg/L an inhibitor for metal ion-induced influence, wherein the inhibitor for emulsified oil-induced influence is selected from AEO-7 and OP-10, the inhibitor for solid suspended matter-induced influence is selected from sodium silicate, sodium carboxymethyl celluloseand polyvinyl alcohol, and the inhibitor for metal ion-induced influence is selected from ethylenediaminetetraacetic acid disodium salt and sodium citrate. The invention further discloses applicationsof the composition. According to the present invention, after the composition is added to the polymer flooding produced water, the stability of the residual polymer can be enhanced, such that the subsequent treatment can be conveniently performed, the residual polymer in the polymer flooding produced water is not easily aggregated, the hydrodynamic radius remains the unchanged state within 24 h,and the passing ability of the micropores is good.