Objectives: This study focused on the identification and characterization of secondary metabolites tentatively from aqueous ethanolic leaf extract of Livistona chinensis by HPLC-PDA-ESI-MS/MS and evaluation of its cytotoxic activity. Methods: The aqueous ethanolic extract was analyzed by high performance liquid chromatography (HPLC) coupled to photodiode array detection of mass spectroscopy (PDA-MS/MS), to detect the secondary metabolites in L. chinensis leaves extract. It was also estimated for its cytotoxicity against human prostate carcinoma (PC3) and hepatocellular liver carcinoma (HepG2) cancer cell lines using SRB (3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. Results: Fortytwo secondary metabolites were tentatively identified; the most major compounds were C-glycoside derivatives of apigenin, luteolin and tricin together with phenolic acids. The 70% alcoholic extract of L. chinensis leaves exhibit more antitumor activity against PC3 than against HepG2. Conclusion: L. chinensis is a privileged source of C-flavonoids that revealed the efficiency of HPLC-MS metabolomics in natural products drug discovery.