Abstract: Non-small cell lung cancer (NSCLC) is a common pathological type of lung cancer, exerting a substantial impact on human health. Therefore, early detection, early diagnosis, and early treatment of lung cancer are crucial for improving the healing rate. Circulating tumor DNA (ctDNA) refers to DNA fragments actively released or passively shed from tumor cells into the peripheral blood circulation system, which has been extensively studied for the detection of lung cancer. In recent years, with the rapid development of ctDNA liquid biotechnology, new advancements have been achieved in the diagnosis and treatment of lung cancer, and it is expected to become a novel approach for various aspects of NSCLC, including diagnosis, treatment guidance, and recurrence monitoring. This article summarizes the current research on ctDNA and discusses the potential application value of ctDNA detection in critical areas such as early screening, recurrence monitoring, treatment regimen formulation, and long-term follow-up management of NSCLC.