OBJECTIVE：To establish the content determination me thod of 3 mono/disaccharides in 3 kinds of medicinal Dendrobii Caulis. METHODS ：HPLC-CAD method was established. The determination was performed on Shodex Asahipak NH2P-50 4E column with mobile phase consisted of acetonitrile-water （75 ∶ 25，V/V）at the flow rate of 1.0 mL/min. The column temperature was set at 30 ℃，and sample size was 10 µL. CAD detection condition included that data acquisition frequency was 5 Hz，filter constant was 5 s，atomization temperature was 35 ℃ ，gas source was nitrogen with pressure of 4.012 × 105 Pa. RESULTS：The linear range of fructose ，D-anhydrous glucose and sucrose were 0.156 2-1.873 8 mg/mL（r＝0.999 5），0.012 7- 0.152 4 mg/mL（r＝0.999 7），0.277 6-3.331 2 mg/mL（r＝0.999 8），respectively. The limits of quantification were 0.002 61，0.004 24 and 0.005 12 mg/mL，and the limits of detection were 0.000 78，0.001 27 and 0.001 54 mg/mL，respectively. RSDs of precision ， stability，reproducibility and durability tests were all lower than 3％. The recoveries were 95.98％-98.15％（RSD＝0.83％，n＝6）， 95.64％-98.62％（RSD＝1.10％，n＝6）and 97.53％-98.94％（RSD＝0.53％，n＝6）. The contents of them were 0.28％-1.12％， 0.02％-0.13％，0.76％-2.67％，respectively. The total content was 1.38％～3.10％. The order of saccharide content in 3 kinds of Dendrobii Caulis was sucrose ＞fructose＞D-anhydrous glucose ；the order of sucrose content and total content were Dendrobium huoshanense＞D. moniliforme ＞D. officinale ；the order of D-anhydrous glucose content was D. huoshanense ＞D. officinale ＞D. moniliforme； the order of fructose content was D. moniliforme ＞D. officinale ＞D. huoshanense . CONCLUSIONS ：Established method is sensitive ，reproducible and simple in operation ，and can be used for content determination of 3 saccharides in 3 kinds of medicinal Dendrobii Caulis. There are differences in the contents of saccharide s among 3 kinds of Dendrobii Caulis.