Objective To study the clinical significance of Carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CY-FRA21-1) ,neuron specific enolization enzyme (NSE) combined detection in the diagnosis of lung cancer .Methods Using the Chemiluminescence to detect the level of CEA ,NSE and CYFRA21-1 in 61 patient with lung cancer (lung cancer group) and 38 pa-tients with benign diseases(control group) .All datas were analyzed with t test .Optimal cut-off point and diagnostic sensitivity ,spe-cificity were obtained by receiver operating characteristic curve (ROC) .Results The level of serum CEA ,NSE and CYFRA21-1 in Lung cancer group was significantly higher than that in control group (P<0 .05) .The expression level of three tumor markers was no statistically significant difference in the different pathological types of lung cancer (P>0 .05) .The cut-off point of CEA was 3 .50 ng/mL ,sensitivity and speciality were 52 .5% ,94 .7% respectively .The cut-off point of CYFRA21-1 was 5 .21 ng/mL ,the sensitiv-ity and specificity were 67 .2% ,93 .1% .The cut-off of point NSE was 18 .09 ng/mL ,the sensitivity and specificity were 77 .0% , 52 .6% .The three combined detection sensitivity was 96 .7% ,significantly higher than separate one(P<0 .05) .Conclusion The three tumor markers(CEA ,CYFRA21-1 ,NSE) might be valuable in the diagnosis of lung cancer .The combined detection could be used as a better pattern for screening lung cancer .