Abstract: Objective To investigate the expression of active RAS，CD68 and CD34 in breast cancer and their clinical significance. Methods Immunohistochemistry was used to detect the expression of RAS， CD68， CD34 in breast cancer tissues. The correlation of the level of RAS with TNM staging， lymph node metastasis， HER-2， ER and PR， tumor size and so on was analyzed. The correlation between RAS and CD68， CD34 expression in breast cancer tissues were investigated. Results Of the 65 cases of breast cancer tissues, 43 cases were positive for RAS and 63 cases were positive for CD68, the median values of CD68 positive cells were 12, and the median value of microvessle density（MVD） was 49. RAS expression level was significantly positively related with length to diameter of tumor and HER2（r=0.342，P=0.005；r=0.334，P=0.006）.CD68 positive cells level was significantly positively related with length to diameter of tumor, TNM staging and HER2（r=0.303，P=0.014； r=0.358，P=0.003；r=0.325，P=0.008）.RAS level was significantly positively related with CD68 positive cells level（r=0.277，P=0.026）. MVD level was positively related with CD68 positive cells level（r=0.330, P=0.007）. Conclusion The horizontal of RAS and the CD68 positive cells in breast cancer are significantly related with HER-2，tumor size，TNM stage. RAS may affect the process of MVD generation promoted by macrophages， and its mechanism still needs to be further studied.