Lung cancer is the malignant tumor with the highest incidence and mortality in China and even worldwide. Non-small cell lung cancer (NSCLC) constitutes the vast majority of cases. The current innovation in lung cancer diagnosis and treatment systems is progressively transitioning from traditional pathological classification to molecular characteristic-guided precision medicine. However, the conventional gold standard for molecular detection-tissue biopsy-faces limitations including invasive procedures and non-repeatable sample acquisition. The breakthrough in liquid biopsy technology has provided new clinical pathways, particularly through circulating tumor DNA (ctDNA) detection for molecular residual disease (MRD) monitoring, which has emerged as a research hotspot in the liquid biopsy field. Through continuous optimization, this approach has achieved breakthroughs in high sensitivity and specificity. Its non-invasive nature eliminates the risks associated with tissue puncture, demonstrating significant potential in various clinical applications including early/advanced NSCLC diagnosis, treatment response monitoring, drug resistance evaluation, and prognosis prediction.