Objective: To determine the content of conduriol A in Guangxi Gymnema sylvestre (Retz.)Schult by TLCS. Method :Silica H thin layer plate was used; the developer reagent was benzene:ethyl acetate:methanol(10 ∶3 ∶5)

the color reagent was 5% vanillin sulfate solution.The plate was at heating on 105 ℃

when the spot was clear; the detection wavelength was 538 nm and the reference wavelength was at 700 nm. Result : The conduriol A was linear in range of 1.025~6.150 μg; the average recovery was 98.84%

RSD=2.02%(n=6).The average content of conduriol A was 2.08% in was simple

sensitive

accurate and had good reproducibility. Conclusion : The method can be used the identification and determination method of Guangxi Gymnema Sylvestre (Retz.)Schult and qualitatively.