Abstract: Analysis of ligustilide in the essential oil and crude drugs of Umbelliferae plants was made by TLC and densitometry. The ligustilide was Separated on silica gel G plate with carbon tetrachloride-xylene-chloroform-hexane (4:3:2:0.5) as the developing solvent. Ligustilide spot was detected at 365 nm and also by spraying with 1% vanillin solution in concentrated sulfuric acid. Quantitative determination was made with a Shimadzu Dual Wavelength TLC Scanner CS-900.The method was sensitive, convenient and rapid. The integrated peak area was proportional to the amount of ligustilide within the range of 0～5 μg. The method had been applied to the determination of ligustilide in essential oils and crude drugs such as Angelica sinensis, Levisticum officinale, Ligusticum jeholense, Archangelica officinalis and Angelica dahurica, etc.The stability of ligustilide on silica gel G plate was examined, no decomposition was observed in two hours. It was shown that the larger the amount of ligustilide applied, the more rapid the decomposition.