To explore the antagonism of ethanol extract from Euphorbia stolondi in tumor and its inhibitory effect on angiogenesis. Methods:Normal cells and tumor cells were cultured, and IC50 was detected by MTT after medication. The primary rat thoracic aorta endothelial cells (RAECs) were cultured and analyzed by iCELLigence method. The effects of Euphorbia extract on the increment, migration and vascularization of RAECs were studied by cell migration method and cell tube group. Western blot technology was used to detect the expression of p-Akt，Akt，p-eNOS，eNOS，TGF-β1，Smad3 and other proteins related with angiogenesis signaling pathways. When the model of human liver cancer established with nude mice carried transplanted tumor after intervened by prostrate Euphorbia alcohol extract, the body weight, tumor size and tumor quality of nude mice were detected, and the levels of vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF-BB) in the serum of nude mice were detected by LISA technique. At the same time, the morphology of transplanted tumor ,which is stainined by HE, is observed. Results:The maximum MTD tolerance of the extract from Euphorbia stolon was 94.29g·kg-1. For the rat myoblasts (L6 cell lines), the prostrate alcohol extract has no obvious inhibitory effect, while the prostrate Euphorbia has convincing inhibitory effect on the rat adrenal pheochromocytoma cell line PC12, human hepatoma cell HepG-2, human non-small cell lung cancer cell line A549 and human cervical cancer cell Hela. In addition, ethanol extract of Euphorbia stolon can increase the RAECs value, migration and vascularization, and also have a significant inhibitory effect. Conclusion:The prostrate alcohol extract can significantly inhibit the growth of tumor and the formation of blood vessels, which may be one of the effective mechanisms of the antitumor effect of the Euphorbia prostrate.