In this study, we carried out quantification analysis of the six marker components, geniposidic acid, chlorogenic acid, geniposide, pinoresinol diglucoside, liriodendrin, and genipin in the 70% ethanol extracts of non-processed Eucommiae Cortex and processed Eucommiae Cortex using a high-performance liquid chromatography coupled with photodiode array detector. The six components were separated on Gemini C18 column (5 μm, 4.6×250 mm) by the gradient elution with 1.0% (v/v) acetic acid in water and 1.0% (v/v) acetic acid in acetonitrile as mobile phase. The flow rate was 1.0 mL/min and the injection volume was 10 mL. The amount of geniposidic acid, chlorogenic acid, geniposide, pinoresinol diglucoside, liriodendrin, and genipin in non-processed Eucommiae Cortex were 1.31, 0.31, 0.66, 0.46, 0.46, and 0.03%, respectively, while the amount of the six compounds in non-processed Eucommiae Cortex were 0.04-0.78, 0.01-0.14%, 0.05-0.63%, 0.01-0.37%, 0.15-0.42%, and not detected, respectively. After processing treatment, the contents of three iridoids, two lingnan, and one phenylpropanoid decreased in Eucommiae Cortex.