Abstract: Objective To investigate the effects of betulin on the expression of matrix metalloproteinase-2（MMP-2） and matrix metalloproteinase（MMP-9）in tumor tissues of nude mice bearing human ovarian cancer xenograft and their significance. Methods The subcutaneous ovarian cancer SKOV3 xenograft model was successfully established in nude mice. Thirty nude mice were randomly divided into 5 groups（n=6）: betulin high-dose group（80mg／kg），betulin medium-dose group（40mg／kg），betulin lowdose group（20mg／kg），control group（normal saline）and paclitaxel group（135mg／m2）. All the mice received intraperitoneal injection once every two days for 21 days at a dose of 0.2ml. Then all the mice were sacrificed；the transplantated tumor mass and volume were measured to calculate the tumor inhibitory rate. The protein expression of MMP-2 and MMP-9 were deteced by immunohistochemical method. Results Tumor volumes and masses of mice treated with betulin and taxol were smaller than those of control group when mice were sacrificed（P＜0.05）. The tumor inhibitory rate of betulin low-dose group was 17.5％，lower than 44.5％ and 51.4％ in medium- and high-dose group（P＜0.05）. The expression of MMP-2 and MMP-9 in control group were（56.78±6.42）% and（69.35±5.03）%, higher than（47.13±8.67）% and （53.82±7.41）% of betulin low-dose group,（38.29±4.37）% and（48.79±4.63）% of betulin medium-dose group, and（26.88±5.12）% and （38.93±2.82）% of betulin high-dose group（P＜0.05）; the expression of the two proteins in the three betulin groups had significance（P＜0.05）. Conclusion The betulin can inhibit the growth of transplanted tumors of ovarian cancer SKOV3 cells in nude mice，which may related to the downregulation of the expression of MMP-2 and MMP-9.