Abstract： Objective To explore the diagnostic value of 3 tumor markers,Carcinoembryonic antigen(CEA),Cytokeratin fragment 21-1(CYFRA21-1)and Neuron-specific enolase(NSE),in different histological lung cancers.Methods Concentration of NSE,CEA and CYFRA21-1 were(8,80±1.63)μg/L,(83.30±3.62)μg/L,(6.90±0.68)μg/L in patients with adenocarcinoma;(8.60±1.47)μg/L,(14.30±3.25)μg/L,(8.30±1.03)μg/L in patients with squamous cell carcinoma and(33.80±4.24)μg/L,(13.60±1.95)μg/L,(34.80±5.64)μg/L in patients with undifferentiated small cell cancer.The concentration of these three tumor markers in lung cancer group were significantly higher than those in benign disease group[(7.80±1.58)μg/L、(7.90±1.12)μg/L、(1.86±1.53)μg/L,(P＜0.01)].The sensitivity of CYFRA 21-1 in squamous cell carcinoma was 72.2%;CEA in adenocarcinoma was 69.8%:NSE in undifferentiated small cell cancer was 63.6%.The sensitivity and specificity of associated tumor markers were 72.9%and 91.4%.Conclusion CYFRA21-1.CEA and NSE are useful for diagnosis of lung cancer with different histological type,especially with combined detection of the 3 serum tumor markers.