Breast cancer, a malignant tumor frequently occurring in females, is traditionally treated with excision. In the search for a new treatment, we analyzed the influence of CoCl2 on MCF-7 cell proliferation of breast cancer and tumor angiogenesis factor and discussed the results. Having applied CoCl2 as chemical hypoxia-induced agent, in-vitro MCF-7 cell hypoxia model of breast cancer was established, after which methyl thiazolyl tetrazolium (MTT) staining was performed in detecting inhibitory action of CoCl2 to proliferation of MCF-7 cells cultured in-vitro, and inverted phase contrast microscope was adopted to observe morphological changes of MCF-7 cell in hypoxia model. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) was made to determine how CoCl2 influences mRNA expression changes of hypoxia inducible factor-1α (HIF-1α), chemokine receptor-4 (CXCR4) and vascular endothelial growth factor (VEGF) in MCF-7 cells. Western blot was designed to study and record data on the influence of CoCl2 on protein expression changes of HIF-1α, CXCR4 and VEGF. As a result, CoCl2 was proved to control MCF-7 cell proliferation and increase expression of HIF-1α, CXCR4 and VEGF.