Abstract: In this experiment we compare two test emthods to determine the serum alpha-1-antitrypsin(α₁-AT) level, the enzymatic and immunoelectrophoresis methods. With the both methods we measure the α₁-AT concentration in the serum of neo-plastic and non-neoplastic lung diseases and varied digestive cancers including hepat-ic, panereatic, esophageal cancers. The results from both test methods give identi-cal finding, which indicate that the serum α₁-AT level of lung cancer is significantly higher than that of normal control(P<0.001) and it is also higher than that of non-neoplastic lung diseases according to only immunologiecal method(P<0.05). The serum α₁-AT level of all determined five sorts of digestive cancers are higher than that of normal control nonspecificly(P<0.001). The results show that, as a sort of acut phase reactants, serum α₁-AT level may elevate in varied cancers non-specificly, and may be higher than that of non-neoplastic disease so it may have clin-ical meaning for diagnosis or screen of these cancers. Comparing the both test meth-ods of serum α₁-AT we think the immunoelectrophoresis method may be better se-lection for clinical usage.