Objective:To optimize the ethanol extraction process and the condition of Danhuang gel for quantified fingerprint technique by uniform design.Method: An U8（82×42） uniform design was used to prepare the samples according to the results and the effects of ethanol concentration

ethanol amount

times of extraction and the number of extraction on the yield of extract by HPLC fingerprint technology.Multi-nonlinear mathematic models were used to estimate the relationship between response index and factor variables with multi-index of the content of chrysophanol and berberine

the total area of characteristic peaks of HPLC and the yield of powdered extract.The response surface and contour plots were delineated according to best-fit mathematic model

and the optimum range of technological parameters and optimum ethanol extraction condition were selected by the response surface and contour plots.Result: Two order quadratic equation described the relationship between response indexes and factor variables with a regression coefficient of 0.983 3.The optimum condition of the ethanol extraction was obtained that the raw material amount was extracted with 7 volumes of 65% ethanol three times for 2 h per extraction process.Conclusion: The extraction method optimized by quantified fingerprint technique combined with uniform design and response surface analysis is stable and feasible.The study could provide the references and groundwork for its further investigation.