Objective:To study effects of tanshinone ⅡA（TSⅡA） that was the active component of traditional Chinese medicine salvia miltiorrhiza to hypodermatic transplanted tumor micrangium growing in colorectal cancer nude mice.Method: Colorectal cancer models in nude mice bear human HCT-116 cells were established

and then were randomly divided into 5 groups: Model group（DMSO group）

TSⅡA low-dose group（0.5 mg ·kg-1 · d-1）

TSⅡA mid-dose group（1 mg · kg-1 · d-1）

TSⅡA high-dose group（2 mg · kg-1 · d-1）

5-Fu group（50 mg · kg-1 · d-1

2 d）.All group of nude mice were sacrificed at the last time treatment for 21 days

the size and weight of tumor were measured;the microvessel density（MVD） was tested by Immunohistochemistry;the vascular endothelia growth factor（VEGF） protein expression in mice serum was assayed by ELISA;the β-catenin expression was detected by Western blot.Result: The inhibition rate of tumor in each group were respectively 25.6%

46.7%

59.6% in low

mid

and high-dose TSⅡA.The MVD in low

mid

high-dose TSⅡA were respectively（60.8±7.0）

（47.5±6.7）

（31.3±4.2） and（20.5±4.1）

which was obviously decreased compared with model group（P<0.01）.The VEGF in low

mid

high-dose TSⅡA was decreased as 0.94 folds

0.84 folds and 0.73 folds compared with model group（P<0.01）.TSⅡA dose-dependently reduced the level of β-catenin in the total cell and nuclear proteins.Conclusion: TSⅡA could inhibited the growth of colon carcinoma implant tumor of nude mice and MVD

which may be due to decreasing β-catenin and VEGF expression.