Objective：To study the difference of proteomic spectra in serum of patients with colorectal cancer(CRC) in order to build a proteomic pattern and find a method for early diagnosis of CRC. 
Methods：We screened for potential tumor biomarkers of serum samples from 48 CRC patients and 34 healthy subjects by using CM10 (Ciphergen Company, USA) and the technology of Surface enhanced laser desorption/ionization time-of-flight mass spectrometry（SELDI-TOF-MS）.Using Ciphergen Protein Chipsoftware 5.1, a proteomic pattern was constructed. The constructed pattern was then tested by an independent set of masked serum samples from 33 colorectal cancer patients and 34 healthy subjects.
Results：(1) The contents of 27 proteins in the  CRC to healthy subjects groups were significantly different (P＜0.05) and the M/Z values of these 27 proteins were from 2770.34Da to 16061.26 Da. There were 18 M/Z peaks highly expressing in CRC patients and 9 M/Z peaks highly expressing in healthy subjects. (2) Protein peaks clustering and classification analyses were performed to build a proteomic pattern by M/Z 2770.34, 7971.57 and 11493.00. There were 38 cases in 48 CRC patients and 32 cases in 34 healthy subjects that were classified correctly in this proteomic pattern, and the sensitivity and specificity was 94.12% (32/34) and 79.17% (38/48) respectively. (3) Furthermore, a sensitivity of 72.73% (24/33) and a specificity of 91.18% (31/34) for the blinded test were obtained when comparing the CRC patients with healthy subjects.
Conclusions：The specific serum protein in patients with CRC can be quickly and exactly diagnosed by SELDI-TOF-MS with high sensitivity and specificity. Finding specific-associated proteins could be valuable targets for the early diagnosis of CRC.