Objective: To study the colorimetric determination of total flavonoids in Resina Draconis. Method: Comparison on the difference of absorption curve was done using the characteristics that total flavonoids of Resina Draconis can produce color with various chromogenic reagents. Result: Resina Draconis colored by HCl-Mg power produce a large absorption peak at 475 nm where the interference is small. It had good stability within 6 h and showed a good linear relationship in the range of 0.012-0.12 g·L-1 (r=0.999 3). And its absorption peak was not much change after colored by other chromogenic agent. Conclusion: AlCl3

NaNO2-Al(NO3)3-NaOH colorimetries usually used for determination of total flavonoids were not suitable for Resina Draconis flavones assay. HCl-Mg powder can be used as chromogenic agent for colorimetric determination of the total flavonoids in Resina draconis. But it still needs to find a suitable reference substance.