Non-small cell lung cancer (NSCLC) accounts for about 85% of lung cancer, and the morbidity and mortality rate of it rank among the highest in the world. Because of the anonymity of onset and progression, patients have lost the best treatment opportunity when they were found. Hence, to prolong the progression-free survival (PFS) and overall survival time (OS) of patients, research groups are committed currently both at home and abroad to the early detection technology research and accurate treatment methodology of NSCLC. Fluid biopsy is a method of diagnosis for some diseases through blood or urine etc., which has the advantages of minimally invasive, high sensitivity and repeatability. This method also contributes to the comprehensive reflection of cancer gene mapping, greatly overcomes the spatial and temporal heterogeneity of focus histology biopsy, and is of profound significance to the discovery of drug resistance targets and the prediction of new drug efficacy and the adjustment of clinical drug regimens. In order to promote the clinical application value of this technique, this paper reviews the advantages and limitations of the early diagnosis and monitoring management of NSCLC by using Circulating tumor DNA (ctDNA) detection in liquid biopsy.