Development of sensitive and cost-effective strategies for detecting influenza viruses is crucial to combat the spread of infectious diseases. In this study, a novel trans-dimensional nanocoral gold foam (NCGF) was fabricated on screen-printed carbon electrodes using hydrogen template electrodeposition method. This unique structure, with interconnected large and small pores, significantly increased the specific surface area and stability of the sensor. Based on this nanostructure, the antibodies were further modified and used for influenza A viruses (IAVs) detection by enzyme-linked immunoelectrochemical method. The combination of the large specific surface area of NCGF and the catalytic reaction of alkaline phosphatase led to a dual amplification of electrochemical signals, enabling ultra-sensitive detection of IAVs. The NCGF-based biosensor demonstrated exceptional stability, sensitivity, and achieved a reliable limit of detection as low as 13.14 fg/mL, which is several orders of magnitude improvement in sensitivity over conventional electrochemical immunosensor. Furthermore, 72 clinical samples were analyzed using a portable detection device that could directly read signals from a mobile phone, and the results correlated well with gold standard PCR method. Overall, this rapid, sensitive, and portable assay provides a valuable option for early viral infection diagnosis.