An analytical method for the determination of tannic acid is proposed by the sequential perturbation caused by different amounts of tannic acid on the Belousov-Zhabotinskii oscillating system. The oscillating system is catalyzed by tetraazamacrocyclic complex [CuL](ClO4)2, where L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The method relies on the linear relationship between the changes in the inhibition time and the logarithm of the concentration of tannic acid. The calibration curve obeys a linear equation very well when the concentration of tannic acid is over the range of 6.25 × 10-7 ~ 1.56 × 10- 5 M (n = 16, R = 0.9984). This analytical method, equipped with a simple instrument, provides a new way to accurate determination of tannic acid.