Objective:To separate chemical indicator and establish a HPLC method for determining the indicator in herbs from Dendrobii Officialis Caulis  Methods:The constituents were separated and purified by column chromatography on silica gel and Sephadex LH-20, as well as the chemical structures were determined by spectral data analyses. Determination of content of 3,4-dihydroxy-5,4’-dimethoxy bibenzyl (DDB-1) was performed by using high performance liquid chromatography. A Phenomenex-C,18, column (250 mm × 4.60 mm, 5 μm) was adopted with a mobile phase of acetonitrile-water, the runs were set at 230 nm  Results:Four stilbenoids compounds were isolated and identified as 3,4-dihydroxy-5,4’-dimethoxybibenzyl, 3,4-dihydroxy-5-methoxybibenzyl, 5-hydroxy-3,4’-dimethoxybibenzyl, 4’-hydroxy-3’, 5’- dimethoxybibenzyl. DDB-1 was selected as an indicator to assess the quality of Dendrobii Officialis Caulis. This indicator showed a good linear relationship within the range of 0.044 ~ 0.44 μg (R,2,=0.999 9). The determination of DDB-1 in tested samples from different production base was most different, and it had little difference between each other if Dendrobii Officialis Caulis harvested in different month  Conclusion:This proposed method was found to be accurate, reliable and simple, providing rapid and special determination of DDB-1, which could be used to control quality of Dendrobii Officialis Caulis.