Objective To investigate the significance of mRNA expression of specific tumor markers in peripheral blood in micro-metastasis of non-small cell lung cancer(NSCLC).Methods The mRNA expressions of CK19,LUNX and CEA in peripheral blood of 52 NSCLC patients and 30 normal subjects(the reference group)who were admitted to the Department of Pathology of Jiangxi Chest Hospital from January 2019 to November 2020 were detected by reverse transcription polymerase chain reaction(RT-PCR)technique.The relationship between micro-metastatic markers and pathological types,degree of differentiation and clinical stages in NSCLC patients was analyzed.Results The mRNA positive rates of CK19,LUNX and CEA in NSCLC group were 38.46%,57.69% and 44.23%,respectively,which were higher than those in the control group(0.00%,0.00% and 0.00%),and the differences were statistically significant(P＜0.05).The positive rate of LUNX mRNA in stage Ⅲof NSCLC patients was higher than that of the patients in stage Ⅰand Ⅱ,and the difference was statistically significant(P＜0.0167).The positive rate of LUNX mRNA in highly differentiated NSCLC patients was lower than that in poorly differentiated and moderately differentiated NSCLC patients,and the difference was statistically significant(P＜0.0167).Conclusion The positive rate of LUNX mRNA expression increases with the increase of TNM stage in NSCLC patients,and decreases with the increase of differentiation degree,which is closely related to the micro-metastasis of NSCLC patients,and can be used as a molecular marker for the detection of micro-metastasis in NSCLC patients,which is of great significance for the early diagnosis of lung cancer metastasis and the guidance of clinical staging and treatment.