Abstract: Objective: To detect the serum proteomic patterns in breast cancer patients by surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS). Methods: Therelative contents of serum proteins of 12 healthy people,10 patients with benign breast diseases and 22patients with breast cancer were detected by WCX2 chip and SELDI-TOF- MS. Results: At the M/Zvalues range from 2000Da to 30000Da, the contents of two proteins (3939.314Da and 3960.478Da)hadsignificant difference in the three groups. Conclusions: SELDI-TOF-MS shows great potentiality forbreast cancer in early diagnosis and screening of tumor biomarkers, and deserves generalization.