Abstract: The optimum technology of extracting aucubin, the bioactive component in Eucommia ulmoides, was studied by orthogonal test. An orthogonal test table L₁₆(4⁵) was used with the factors of extracting time, temperature, times, ethanol concentration and the ratio of solid to liquid.The content of aucubin was determined by spectrophotometry.The optimum technology was:temperature 70℃, time 0.5 h, three times, 80% EtOH as extracting solvent, stock ratio 1:9.Under this condition, the best raw material of E.ulmoides for extracting aucubin was chosen, namely the freshly dried bark.

Key words: Eucommia ulmoides Oliver, aucubin, orthogonal test