Abstract: Three compounds were isolated from the roots of Rosa multiflora Thunb. They were identified to be β-sitosterol, 2α, 19α-dihydroxy ursolic acid (Ⅰ) and 2α, 19α-dihydroxy ursolic acid-(28-1)-β-D-glucopyranosyl ester (;dl2y spectroscopic analysis (UV, IR, MS, ¹HNMR and ¹³CNMR) and chemical evidence. The third compound is a new triterpenoic acid sugar ester, named as rosamultin (Ⅱ), C₃₆H₅₈O₁₀, mp 208～210℃, α_D=+10° (c=3.30, EtOH). In pharmacological and preliminary clinical tests the roots of Rosa multiflora Thunb exhibited hypolipidimic activity.