Objective: To screen out the protein showing most significant differential expression in colorectal cancer (CRC) tissues through proteomic technique, and then to analyze its relation with the disease profile. Methods: The surgical specimens from 83 CRC patients were collected, which included the CRC tissues, normal colonic mucosal tissues, metastatic lymph nodes and concomitant benign colonic polyps from some of the patients. Proteomics analysis that consisted of 2D differential gel electrophoresis (2D DIGE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) was performed in CRC and normal colonic mucosa tissues. The protein of interest was validated by Western blot analysis in CRC and normal colonic mucosal tissues along with different CRC cell lines, after it was identified. The expression of this protein was also determined by immunohistochemical staining in the paraffin-embedded specimens of CRC tissue, normal mucosal tissue, benign polyp and lymph node metastasis. Western blot was performed to observe the changes of the protein expression in CRC cell lines after induction of differentiation by sodium butyrate (NaB). Results: The results of 2D DIGE analysis and MALDI-TOF-MS identification showed that the expression abundance of selenium binding protein 1 (SELENBP1) in CRC tissue was significantly decreased (2.54 folds) compared with mucosal tissue (P<0.01). Western blot analysis showed that the SELENBP1 expression level in CRC tissue was significantly lower than that in their paired normal mucosal tissue (0.76±0.37 vs. 1.46±0.56) (P<0.001), and SELENBP1 expression was generally decreased in CRC cell lines. Immunohistochemistry analysis showed that the expression scores of SELENBP1 protein in CRC and normal mucosal tissue were 1.25±0.78 and 2.02±0.77 respectively, with statistical significance (P<0.001); in well, moderately and poorly differentiated CRC tissues were 1.75±0.53, 1.29±0.41 and 0.89±0.49 respectively, with statistical significance (P<0.05); no statistical difference was found among different stages of CRC tissues, between benign polyp and normal mucosal tissue or between metastatic lymph node and primary tumor (all P>0.05). The SELENBP1 expressions in all the tested CRC cell lines were significantly increased following NaB induced differentiation (all P<0.05). Conclusion: SELENBP1 suppression is decreased in CRC tissue, and its decrease is associated with the degree of poor differentiation of CRC, but irrelevant to disease progression and lymph node metastasis.