The invention provides a method for evaluating the effective action distance of acid liquor on basis of the limit of reacted acid. The method comprises the following steps: the effective action distance of acid liquor is evaluated through evaluation of the limit of reacted acids of crosslinked acid, gelled acid and diverter acid according to a method for determining the concentration of hydrogen ions in an acid fluid system. When reacted acid is prepared, the stratum acid rock reaction condition is simulated by using excessive rock to fully react with acid, therefore the property of the obtained reacted acid is similar to that of stratum reverse discharging reacted acid in practical construction; by measurement of the pH values of fresh acid and reacted acid under the formation temperature, the limit of reacted acids of the crosslinked acid, gelled acid and diverter acid fluid systems can be quickly and accurately evaluated and measured, errors of a conventional titration evaluating method can be eliminated, the effective action distance of acid liquor is obtained by substituting the limit of reacted acid into the acid concentration and effective action distance simulated diagram, the evaluation time is short, the evaluation cost is low and a theoretical support is provided for acid fracturing design.