The invention relates to a polypeptide specifically bound with the surfaces of colon 
cancer cells and application of the polypeptide. A method for screening the polypeptide includes steps of (1), incubating clone strains with amplified 
bacteriophage dodecapeptide libraries and the colon 
cancer cells together, discarding the clone strains which are not bound with the colon 
cancer cells, screening the clone strains and then amplifying the screened clone strains which are bound with the colon cancer cells; (2), repeatedly carrying out the step (1) by four times, continuously enriching 
bacteriophage clone strains to obtain clone strains with high 
colon cancer cell affinity and repeatedly verifying the binding capacity of the 
bacteriophage clone strains in liquid phases; (3), incubating the bacteriophage clone strain obtained at the step (2) and normal colonic epithelial cells and removing non-specifically bound clone strains; (4), carrying out sequencing on positive clone strains; (5), verifying the specificity of the polypeptide on the clone cancer cells and tissues by the aid of 
immunofluorescence. The polypeptide and the application have the advantages that short peptides which are specifically bound with the colon cancer cells are screened by the aid of technologies for displaying 
peptide libraries by the aid of bacteriophage, and the polypeptide can be used as a 
molecular marker or targeted carrier or the like for targeted therapeutic medicines.