Combining the specific molecular recognition reaction between biotin and streptavidin with a dual-class signal amplification system, containing the unique optical properties of gold nanoparticles and the catalytic reaction of horseradish peroxidase, a double-enhanced strip biosensor was designed for the first time for a visual and rapid detection of protein biomarkers with good accuracy, especially for CEA with a detection limit of 2.9 fg mL(-1).