Abstract:By establishing H22 transplanted tumor model in mice，observe the inhibitory effect of ursolic acid（UA）extracted from hippophae rhamnoides L.on H22 transplanted tumor in mice and explore its possible mechanism.The inhibition rate and organ index were calculated according to the formula.Hematoxylin-eosin staining（HE）staining was used to observe the histopathological changes of tumor tissues in mice，and the levels of interleukin-12 （IL-12）and tumor necrosis factor-α（TNF-α）in the plasma of the tumor bearing mice were detected by enzyme linked immunosorbent assay.Immunohistochemical staining had been used to detect the positive level of matrix metalloproteinase-2 （MMP-2）in neoplasm tissues.And the expression of vascular endothelial growth factor （VEGF）and Ras protein in tumor tissues was detected by Western blot.The results showed that Hippophae rhamnoides L.abstract ursolic acid could obviously improve the general condition of H22 tumor bearing mice.Restrain the growth of neoplasm in H22 tumor bearing mice，and theneoplasm suppressor rate was 17.46%，35.11 % and 55.22% successively.Compared with the model group，ursolic acid extracted from Hippophae rhamnoides L.could significantly increase the levels of TNF-α and IL-12 （P＜0.05），reduced the positive expression of MMP-2，and down regulated the overexpression of VEGF and Ras，and showed a dose effect relationship.Its mechanism might be related to increasing the concentration of anti tumor active cytokines such as IL-12 in blood to induce cell immunity，improve the immunity of the body，inhibit the degradation of the extracellular matrix of liver cancer and the formation of neovascularization.