To investigate the anti-liver cancer effects and aspartic acid (Asp)-related action mechanism of Euphorbia fischeriana Steud. (Lang Du, LD). The mice model of liver cancer was established by injection of H22 cells. After 5 days, mice were randomly divided into model group, sorafenib group (20 mg/kg), LD high-dose (LDH, 1.36 g/kg) group, LD medium-dose (LDM, 0.68 g/kg) group, and LD low-dose (LDL, 0.34 g/kg) group, 10 mice each group. Drugs were intragastrically administered to the mice once daily for 10 days, respectively. Body weight, tumor size and tumor weight were recorded. Hepatic index was calculated. Pathological changes of liver cancer tissues were evaluated by hematoxylin and eosin staining and TUNEL staining. Liquid chromatography-mass spectrometer was used to analyze different metabolites between the model and LDH groups. After LD treatment, tumor weight, tumor size and hepatic index were reduced compared with the model group. Necrocytosis and karyorrhexis of tumor cells were found. Moreover, 61 differential metabolites (18 up-regulated, 43 down-regulated) were affirmed and 20 pathways of KEGG (P<0.05) were gotten. In addition, Bel-7402, HepG2 and H22 cell viabilities were significantly increased after adding Asp into the medium. And then, the cell proliferation effect induced by Asp was ameliorated by LD. The anti-liver cancer efficacy of LD extract was validated in H22 mice model, and inhibition of Asp level might be the underlying mechanism.