Abstract:A TLC-densitometric method for the determination of oesculetin in Semen Euphorbia lathyridis (Euphorbiae lathyrdis) was established, and esculetin content in Semen Euphorbia lathyridis from three different producing areas (Zhengzhou ,Chengdu and Chongqing)was determined. The method is accurate, sensitive and simple. The recovery is 98.63% and the coefficient of variation is 1.59% (n=5). The esculetin average contents in the three samples are 0.3013%, 0.2046% and 0.2094% respectively.