Abstract: Abstract Aim： To observe the effect of ursolic acid(UA) on the proliferation of rat vascular smooth muscle cell(VSMC) induced by high-level glucose and explore its relationship with p38MAPK signal transduction pathway. Methods： The proliferation of VSMC induced by high-level glucose(25 mmol/L glucose) was adopted as model，the inhibition of UA on the proliferation of VSMC was measured by MTT assay，and the expression levels of phospho-p38MAPK was detected by cell-based ELISA as well as the expression of c-fos protein was examined by SABC method. Results： UA(20 μmol/L and 40 μmol/L) inhibited glucose-induced proliferation of VSMC (P<0.05).Compared with the group subjected to glucose induction，UA decreased the expression levels of phosphorylated p38MAPK(P<0.05)，and also inhibited c-fos expression. Conclusion： UA suppressed glucose induced proliferation of VSMC，which might be related to the suppression of the activation of p38MAPK signal transduction pathway，and thereby down-regulated c-fos expression.