OBJECTIVE： To optimize the ethanol extraction technology of total alkaloids from Shuanghu capsules. METHODS： Using dendrobine as control， the contents of total alkaloids from Dendrobium nobile and Dendrobium officinale in Shuanghu capsules were determined by acidic dyes colorimetry. Using comprehensive scores calculated by the yield of the extract and the contents of total alkaloids as evaluation indexes， the effects of soaking time， ethanol volume fraction， extraction time， solid-liquid ratio and extraction times were investigated with single factor tests. L9（34） orthogonal test was used to optimize ethanol volume fraction， extraction time， solid-liquid ratio and extraction times according to the results of single factor test. The optimized technology was validated. RESULTS： The linear range of dendrobine were 4.16-14.56 μg/mL （r＝0.999 2）. RSDs of repeatability and precision tests were all lower than 5％. Average recovery tests were 93.01％ （RSD＝1.97％， n＝6）. The optimal ethanol extraction technology included soaking for 12 h， ethanol volume fraction of 70％， solid-liquid ratio of 1 ∶ 12 （g/mL）， extracting for 28 min， extracting 3 times. Results of validation test showed that the average yield of extract was 12.80％ （RSD＝4.39％， n＝3）， and the content of alkaloids was 0.359 0 mg/g（RSD＝0.66％， n＝3）. CONCLUSIONS： Established acidic dyes colorimetry is simple， precise and accurate， which can be used for the content determination of total alkaloids. The optimized ethanol extraction technology is stable and feasible， and can be used for the extraction of total alkaloids from Shuanghu capsules.