Three new triterpenoid saponins, julibroside J(29) (1), julibroside J(30) (2), and julibroside J(31) (3), were isolated from the stem bark of Albizia julibrissin Durazz. (Leguminosae) by using chromatographic method. Their structures were established by spectroscopic methods. Compounds 1, 2, and 3 displayed significant anti-tumor activities in vitro against PC-3M-1E8, HeLa, and MDA-MB-435 cancer cell lines at 10microM assayed by SRB and MTT methods.