Benincasa hispida (Thunb.) Cogn. fruits are widely consumed in China and tropical countries. This study identifies three new triterpenoids, 3α,29-O-di-trans-cinnamoyl-D:C-friedooleana-7,9(11)-diene (1), oleanolic acid 28-O-β-d-xylopyranosyl-[β-d-xylopyranosyl-(1→4)]-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (2), and oleanolic acid 28-O-β-d-glucopyranosyl-(1→3)-β-d-xylopyranosyl-[β-d-xylopyranosyl-(1→4)]-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (3), together with 12 known compounds, multiflorenol (4), isomultiflorenyl acetate (5), stigmasterol (6), stigmasterol 3-O-β-d-glucopyranoside (7), α-spinasterol (8), α-spinasterol 3-O-β-d-glucopyranoside (9), β-sitosterol (10), daucosterol (11), arbutin (12), nicotinic acid (13), (+)-pinonesinol (14), and ethyl β-d-glucopyranoside (15). The structures of compounds 1-15 were determined by spectroscopic and chemical methods. All the compounds with the exception of 4, 5, and 9-11 were isolated from B. hispida for the first time. The anticomplement activities of compounds 1-15 were assessed by Mayer's modified method. Compounds 1-15 showed no significant cytotoxic activity against HeLa human cervical, HL-60 human hepatoma, and SMMC-7721 human hepatoma cell lines.