A new current-suppression-type electrochemical immuno-sensor with enhanced sensitivity for the detection of alpha-fetoprotein was developed based on the ease of preparing gold nanorods to immobilize a-fetoprotein antibody coupled with silver nanoflower deposition, to act as a redox mediator, on a Au electrode. The interaction of antigen and antibody on the electrode interface makes a barrier for electrons and inhibits electro-transfer, resulting in decreased DPV signals of nano-Ag.