Abstract： Objective To study the expression of tumor necrosis factor -α (TNF-a) and correlation with TNF-a in breast cancer. Methods We used SABC method to detect the expression of TNF-a in 112 cases of primary breast cancer, and analysis the relationship between TNF-α with histologic grades and ER. Results The positive expression rate of TNF-α in breast cancer was higher than those of normal tissues and lobular hyperplasia of the breast (X2 =8.573, P =0.014). There was no significant correlation between histologic grades and TNF-α (X2 =1.304, P =0.521). TNF-a had a positive correlation with ER in breast cancer (X2=11.949, P =0.001). Conclusion The positive expression rate of TNF-α in breast cancer was higher than those of normal tissues and lobular hyperplasia of the breast.TNF-α had a positive correlation with ER in breast cancer, but the exact mechanism is unclear.