Abstract: A simple, rapid, sensitive and accurate method for the separation and determination of combined sugars in glycosides is described. Glycoside solution is applied at a point about 1 cm from the bottom edge of the HPTLC silica gel plate (10×10cm) and is hydrolysed with hydrogen chloride vapor for 20 min at 50～60℃. 1 ml of glacial acetic acid is added to 9 ml of the lower layer of a mixture of chloroform-methanol—water(30:12:4)which is used as the developing solvent, the plate is saturated for 90 min and then developed for 9 cm using ascending technique. The plate is soaked into a coloring reagent of 0.93 g of aniline and 1.66 g of o-phthalic acid in 100 ml of n-butanol, then heated for 15 min at 100℃ to intensity the coloured spots. The spots are scanned with a Shimadzu CS-930 TLC scanner. The molar ratio of sugars in glycosides is calculated by comparison with standards spotted on the same plate.0.1μg of glycosides is applied, the linear range is 0.1～1.0μg. The correlation coefficients of rhamnose, arabinose and glucose are 0.998, 0.999 and 0,999 respectively. The spots are stable for more than 1 h and the variation coefficient is less than 3%.