Abstract: OBJECTIVE To elaborate the correlation between chromatography fingerprint of Astragali Radix and the efficacy of diuretic effect, and express the effective substances foundation. METHODS To study different origin Astragali Radix of HPLC fingerprints of the ethyl acetate extracts of 10 batches, and the ethyl acetate extract was given to mice by gavage for 7 d (1.4 g·kg^-1). Hydrochlorothiazide was used as a positive control, Urine volume was set as the index of diuretic effect evaluation. Then the grey relational analysis was used to study its spectrum-effect relationship. RESULTS The efficacy of diuretic of the total ethyl acetate extract part of Astragali Radix resulted in its chemical compositions together. Its various peaks represented different chemical components. The contribution order of diuretic effect was(number of peaks): P₇>P₆>P₈>P₅>P₄>P₂>P₁>P₃, in which the number of peaks of 4 was identified as calycosin, peak of 7 was formononetin. CONCLUSION There are many flavonoids with middle polarity in the ethyl acetate extract, which might obviously increase the urine volume of mice. There is a responsible relationship between the HPLC fingerprints and efficacy of diuretic effect. It is also the foundation for further study to nephritis proteinuria.