Two novel rearranged oleanane-type triterpenes, dysoxyhainanin A ( 1) possessing a unique 1,3- cyclo-2,3- seco A ring with a formamido-containing appendage and dysoxyhainanin B ( 2) featuring an unprecedented 1,2-dinor-3,10:9,10- bisseco skeleton, were isolated from Dysoxylum hainanense. Dysoxyhainanin A ( 1) exhibited significant antibacterial activity against Gram-positive bacteria.