The extracts from Chinese herbs are complex compounds with uncertain mechanism, which affects the target with all ingredients. Therefore, it is of great importance to evaluate the bioactivity of these extracts. In this study, 29 samples which had continuous variation of constituents were obtained from the alcohol extract of Terminalia chebula Retz. by a Sephadex LH-20 size exclusion chromatographic column. After detecting the chromatographic information of detection wavelength at 254 nm and the activity information of these samples, the mathematical relationship equation was established to determine the impact on the active components. Stepwise regression method was used to research the relationship between the peak areas (V(i), independent variables) of the compositions in the samples and activities (according to the enzyme inhibition (W), dependent variables). The results showed that there were 55 chromatographic peaks in the samples and the mathematical relationship between the compositions of Terminalia chebula Retz. extract (V(i), i = 1, 2, ..., 55) and activities was certain. The expression was: W = V(7) x (-0.034 +/- 0.013) + V18 x (-0.155 +/- 0.051) + V29 x (-0.142 +/- 0.028) + V4 x (0.079 +/- 0.020) + V11 x (0.074 +/- 0 028) + V36 x (-0.117 +/- 0.053) + 85.669 +/- 4.476, multiple correlation coefficient R = 0.854, significance level (Sig. F change) = 0.037. The steadiness of model was favorable with new digital information. The compounds corresponding to 18th, 29th, 36th, 4th, 11th and 7th peaks were the main active compounds. The method can be also applied to the relationship between a wide variety of components of traditional Chinese medicine resources and different kinds of activities. It is significant to the research and development of traditional Chinese medicine.