Aim To establish the method for determination of benzofuranones derivative, griffonilide, in the roots of Semiaquilegia adoxoides (DC.) Makino by RP- HPLC. Methods Kromasil C18 column was used with a mobile phase of methanol-water ( containing 0. 01% trifluoroacetic acid and 0. 05 % tetrahydrofuran) (3:97). The detecting wavelength was 260 nm. Results The calibration curve was linear over the range of 0. 004 - 0. 4 mg·mL^-1 with the correlation coefficient of 1.00 000. The average recovery was 98. 77 % with RSD 2. 77 %. Determinations of ten samples from different areas showed that the contents of griffonilide in the roots of S. adoxoides are 0. 17 -0. 49 mg·g^-1. Conclusion The method provides an accurate and sensitive way to detect griffonilide in the roots of S. adoxoides .