Objective: Studies have shown that TNF-αsecreted by tumor cells and macrophages infiltrated into the tumor microenvironment might promote the metastasis of a variety of malignant cancers, including breast cancer. The present study was designed to detect global metastasis-related gene expression changes of MCF-7 cells treated by low dose TNF-α and to further explore the mechanisms by which TNF-αcontributes to metastasis. Methods: MCF-7 cells were cultured and treated with low dose TNF-α(20 ng/ml). cDNA array analysis was applied to detect the metastasis related gene expressions. Results: A total of 36 gene expressions were significantly regulated by TNF-α. Functional analysis indicates that the altered genes belong to different functional group. Most of the genes changed may promote the metastasis of MCF-7 cells while the others may inhibit metastasis. The changes observed in gene expression following TNF-αwere somewhat time dependent. Conclusion: TNF-αcan enhance the invasive ability of MCF-7 cells, partly by regulating a series of metastasis related genes, and these genes may take part in every step of metastasis. Some of the genes deserve further study.