Abstract: Serum Lipid-bound Sialic Acid(LSA), Human Chorionic Gonadotropin(HCG), β₂-Microglobu-lin(β₂-MG) and Carcinoembronic Antigen(CEA) were measured in 94 prooperation and 34 postoper-ation of lung neoplasmas. The results showed that these four indexes were higher in lung cancer than those in normal controls, especially highest in adenocarcioma, and the decreased in postoper-ation, but increased in turn from Term Ⅰ to Term Ⅳ. The sensitivity and accurasy of LSA on diag-nosis of lung cancer was superior to HCG and β₂-MG. The serum level, sensitivity and accurasy of LSA were higher in adenocarcinoma, whereas LSA & HCG were higher in aquamous carcinoma, HCG & β₂-MG were higher in Small Cell Lung Carcinoma(SCLC). Conbined measurement of these four indexes contributed to the diagnosis, differiation, and recurrence of postoperation.