Abstract: In the present study, one new cycloartane triterpenoid, named cycloccidentalic acid C ( 1 ) and its glucoside, cycloccidentaliside Ⅵ ( 2 ) were isolated from the whole plant of Cassia occidentalis. Their structures were elucidated by a combinational analyses of 1D and 2D NMR data and HRMS. Compound 2 showed modest anti-HIV-1 activity with EC₅₀ value of 1.44 μmol·L^-1 and TI (Therapeutic Index) value of 15.59.