TNFAIP1 was first identified as a tumor necrosis factor alpha(TNFalpha) and interleukin-6 (IL-6) inducible protein. Experiments on human and rat suggested the protein may play roles in the DNA repair, DNA synthesis, cell apoptosis and human diseases. But its real function and mechanism have not been reported. In this paper, the expression of TNFAIP1 were determined in a number of cell lines by Real-time PCR. We found that the expression levels of TNFAIP1 are high in COS7 and NIH3T3 cell lines but low in the cancer cell lines. These suggest that TNFAIP1 may be involved in the process of cancer. The over-expression of human TNFAIP1 can accelerate the apoptosis of HeLa cell.