A murine primary mammary tumor model was established to investigate the treatment with ginsenosides Rg3. The relationship between ginsenosides Rg3 and primary mammary tumor was explored. Mammary tumor was induced by using the 7,12-dimethybenz(a)anthracene (DMBA). Ginsenoside Rg3 was employed for treatment. The incidence of mammary tumor in every group was compared, and the expressions of vascular endothelial growth factor (VEGF) and microvessel density (MVD) were detected by immunohistochemical method. The cell cycle and apoptosis percentage were determined by means of flow cytometry. The incidence of tumor in treatment group was significantly lower than that in control group (60.00% vs 33.33%, P<0.05). The average diameter of mammary tumor was (0.86±0.27) cm in control group and (0.39±0.09) cm in treatment group, with the difference being significant between control and treatment groups (P<0.01). The MVD value was (31.9±5.3) in control group and (20.1±4.9) in treatment group, respectively. There was a significant difference between the two groups (P<0.05). The apoptosis percentage in control group was significantly lower than that in treatment group [(2.47±0.69)% vs (5.67±0.99)%, P<0.05]. Ginsenoside Rg3 can play an antitumor role in primary mammary tumor model by inhibiting angiogenesis, cell cycle progression, and promoting cell apoptosis.