One new pentacyclic triterpenoid, 3β-carboxylicfilic-4(23)-ene (1), and three known pentacyclic triterpenoids, adian-5-en-3α-ol (2), fernenol (3), and fern-7-en-3β-ol (4) were isolated from the petroleum ether phase of the ethanolic extract of Ainsliaea yunnanensis Franch. Their structures were