Integrin is important for cell growth, invasion and metastasis, which are frequently observed in malignant tumors. The periostin (POSTN) gene encodes the ligand for integrin, one of the key focal adhesion proteins contributing to the formation of a structural link between the extracellular matrix and integrins. High expression levels of the POSTN gene are correlated with numerous human malignancies. We examined POSTN protein in colorectal cancer specimens from 115 patients by strictly following up using immunohistochemistry. Cytoplasm immunohistochemical staining showed POSTN protein expression in colorectal cancers. The positive expression rate of POSTN protein (59.13%, 68/115) in colorectal cancers was significantly higher than that in adjacent normal colon mucosa (0.47%, 11/109). POSTN over-expression in colorectal cancers was positively correlated with tumor size, differentiation, lymph node metastasis, serosal invasion, clinical stage and five-year survival rates. Further analysis showed that patients with advanced stage colorectal cancer and high POSTN expression levels had lower survival rates than those with early stage colorectal cancer and low POSTN expression levels. Overall, our results showed that POSTN played an important role in the progression of colorectal cancers.