To explore the feasibility of surface-enhanced Raman scattering (SERS) labeled immunoassay technology for clinical analysis protein expression in colon cancer tissue sections, we develop 4-mercaptobenzoic acid (4-MBA) labeled Au/Ag core-shell nanoparticles (NPs) as assay platform for the detection of carcinoembryonic antigen (CEA) in colon cancer tissue samples. Firstly, Raman active molecule 4-MBA is adsorbed on Ag shell Au core bimetallic NPs, and then the SERS-tagged nanoprobes are modified with CEA monoclonal antibody, forming CEA-SERS probes. Finally, according to the theory of specific binding of SERS-tagged antibody and the corresponding antigen, SERS spectra and imaging are performed in tissue sections after dropping the SERS-tagged immuno-nanoprobes. Data show that colon cancer epithelium appears strong SERS signals, while stroma and normal epithelium do not appear SERS signals, except a few non-specific adsorption signals. As can be clearly seen from the SERS images, the colon cancer epithelium highly expresses CEA, while stroma and normal epithelium do not. In conclusion, due to high sensitivity and high specificity of SERS-tagged immuno-nanoprobes, the SERS labeled immunoassay technology is promising for the analysis of the protein expression in colon cancer tissue sections and has the potential to be developed into a significant aiding tool for pathological diagnosis of colon cancer.