Abstract: Objective To approach whether Celeoxib could be used to cure breast cancer,the protein and mRNA level of COX-2 in breast cancer tissues and breast cancer cell lines MCF-7 and B37 was detected,and MCF-7 cells were cultured with Celecoxib to observe the effect of Celecoxib on proliferation and apoptosis of breast cancer cell lines. Methods Immunohistochemical staining,in situ hybridization and RT-PCR were used to detect the expression of COX-2 protein and mRNA in breast cancer tissues and breast cancer cell lines MCF-7 and B37; MTT assay and AO/EB double-staining were used to show effect of Celecoxib on proliferation and apoptosis of breast cancer cell lines. Results COX-2 protein mRNA could be detected in both the breast cancer cell lines MCF-7 and B37,and 52.3% of breast cancer tissues could express COX-2 protein; Celecoxib could inhibited MCF-7 cell growth in a concentration and time-dependent manner,and could lead to the 38.5% cell apoptosis of MCF-7 cell. Conclusion Breast cancer cell lines MCF-7,B37 and breast cancer tissues expressed COX-2; Celecoxib could inhibit breast cancer cell proliferation and induce apoptosis,with indicating that Celecoxib can be used as a new chemical drug treatment for breast cancer.