Abstract:From the roots of Rubia yunnanensis, two new arborane type triterpenoids, rubiarbonone B and C were isolated and their structures were elucidated as 7β, 19α, 28 - trhydroxyarbor - 9 (11) - en - 3 - one and 28 - acetoxyl - 7β, 19α - dihydroxyarbor -9(11) - en - 3 - one respectively by spectral and chemi-cal methods.