In order to understand the difference of contents of coelonin,batatasin Ⅲ and 3'-O-methylbatatasin Ⅲ in 60 different sources of Bletilla striata planted under the same conditions. UPLC method was used and the analysis was performed on a Waters ACQUITY UPLC BEH C18 column( 2. 1 mm×100 mm,1. 7