Objective To investigate the effect of Yiqi Huoxue Huatan Decoction(YHHD) on gene expression of vascular endothelial growth factor(VEGF), intercellular adhesion molecule 1(ICAM-1) in the colonic mucosa of ulcerative colitis rats. Methods Sixty rats were divided into six groups, namely normal control group, model control group, low-, middle- and high-dose Y HHD group(gastric gavage of YHHD in the dosage of 13, 26, 52 g·kg-1·d-1 respectively) , and Mesalazine(0.5 g·kg-1·d-1 ) group. T he rat model of ulcerative colitis was established by enema with 2, 4, 6-trinitrobenzene sulfonic acid(TNBS)mixture(2.5%TNBS and 50% ethanol). The changes in rat body weight were monitored. After treatment, pathological features of the colonic mucosa were observed under light microscope, and VEGF and ICAM-1 gene expression levels in the colonic mucosa were measured by reverse t ranscripti on polymerase chai n reaction(RT-PCR). Results Body weight was lighter, and relative gene expression levels of VEGF and ICAM-1 in the model group were significantly higher than those in the normal control group, and pathological features of the colonic mucosa was obvious, the differences being significant between the two groups(P<0.01). Compared with the model group, body weight was increased , pathological features of the colonic mucosa were relieved, and relative gene expression levels of VEGF and ICAM-1 were significantly decreased in YHHD groups(P<0.01), and high-dose YHHD showed the strongest effect. Conclusion YHHD can down-regulate the gene expression of VEGF and ICAM-1, which may be one of its therapeutic mechanisms for ulcerative colitis.