Early diagnosis of diseases is essential for improving the prognosis of the patients, particularly for those with major chronic diseases, such as cancers, as early and precise diagnosis can significantly enhance the survival rates of the patients and reduce their healthcare burdens. In recent years, the in-depth integration of biosensing technology and DNA nanotechnology has greatly promoted the rapid advancements in the biomedical field, effectively overcoming the limitations of traditional diagnostic methods and enabling the transition of disease diagnosis to more accurate molecular phenotypic analysis. This advancement has substantially improved the sensitivity, specificity, and real-time monitoring capabilities of the biosensing techniques, providing powerful tools for early disease diagnosis and progression monitoring. This paper, taking the work of our team in recent five years as an example, systematically introduces the progress in biosensing techniques focusing on life and health, particularly highlighting the development of the biosensing techniques in the detection of different biomarkers, such as tumor cells, extracellular vesicles, and bacteria. These developments may pave the way to promote the early screening and precise intervention of major chronic diseases.