Ultrafine conductors, with their unique small size, excellent electrical properties, and mechanical flexibility, are driving the development of medical devices towards miniaturization, precision, and intelligence. They have brought revolutionary changes to fields such as interventional diagnosis and treatment, wearable devices, and neuroscience. With the continuous advancement of materials science, micro-nano processing technology, and biocompatibility research, we will see more innovative medical devices based on ultrafine conductors in the future, opening up new avenues for disease diagnosis, treatment, and health management.