A novel molecular imprinted polymer (MIP) electrochemical sensor was successfully fabricated for sensitive detection of carcinomaembryonic antigen (CEA). We used CEA as template, dopamine (DA) as imprinted monomers. Through controlling electropolymerization, a "PDA-CEA"complex was achieved. After elution, the specific cavities adsorbed the target molecules. In addition, polythionine (PTh) and AuNPs were applied as the electrode modifying materials to enhance electron transfer rate and improve detection signal. Using differential pulse voltammetry (DPV) detection, the peak current decreased with the increase in concentration of CEA, and the linear response range of the MIP sensor was from 0.001 ng/mL to 1000 ng/mL with the detection limit as low as 0.2589 pg/mL. The MIP sensor had a low sample consumption, good stability, and high sensitivity, and could become a new promising method for the detection of CEA. Furthermore, this MIP sensor was demonstrated in testing CEA in human serum sample with satisfactory results.