Objective:To compare the diagnostic value of serum tartrate-resistant acid phosphatase 5b(Tracp5b), cancer antigen 153(CA-153) and carcino embryonic antigen(CEA) in patients with bone metastases of breast cancer. Methods:The serum levels of Tracp5b, CA-153 and CEA were determined by enzyme-linked immunosorbent assay and electrochemiluminescence in 26 breast cancer patients without bone metastases, 32 breast cancer patients with bone metastases and 18 healthy female adults. Results:The serum levels of Tracp5b in breast cancer patients with bone metastases were significantly higher than those in other two groups(P < 0.05). The sensitivity and specificity of Tracp5b to bone metastases was 78.13% and 86.36%. The sensitivity and specificity of CA-153 to bone metastases was 37.50% and 77.27%, and those of CEA were 21.88% and 84.09%, respectively. The sensitivity of Tracp5b were significantly higher than those of CA-153 and CEA(P < 0.05). Conclusion:Tracp5b is a useful serum marker to diagnose bone metastases in breast cancer patients.