Carboplatin, efficient cytostatics for cancer therapy, could induce apoptosis and inhibit the growth of vascular endothelium in several tumor cell lines and xenograft models. It has been suggested that the antitumor effect of chemotherapy could be increased by combining it with an antiangiogenesis agent in anticancer strategy. The present study explored the potential to increase the antitumor effect of carboplatin by combining it with thalidomide in mouse 4T1 breast cancer models, and the underlining mechanism was investigated. The systemic administration of carboplatin and thalidomide significantly decreased tumor growth through increased tumor cell apoptosis compared with either control group. Collectively, these findings suggest that combined treatment has shown synergistic suppression in tumor progression according to the analysis. Furthermore, also was observed reduction in number of lung metastases as compared to isolated treatments and increased survival of the animals. The present study may be important in future exploration of the potential application of the combined approach in the treatment of breast cancer.