【Abstract】Objective To investigate the experimental conditions of radionuclide iodine (131I) labeling epidermal growth factor receptor (EGFR) monoclonal antibody (McAb) 1H12 , observe the cell-binding function and biological effects of 131I-1H12 to A549 human lung cancer cells. Methods 1H12 was labeled with 131I by IODO-GEN method. The immunocompetence of 131I-1H12 was analyzed by cell-binding test. The cell apoptosis and cell cycles of A549 was analyzed by flow cytometry assay with various doses of 131I-1H12（148、74、37kBq）,free131I （148kBq）,1H12（80nmol/ml）and equivalent medium. Results The labeling rate of 131I-1H12 was 50.14%, its specific activity, radioactive concentration and radiochemical purity were 4.63MBq/ug,77.31MBq/ml and 96.92% separately. The specific binding rate of 131I-1H12 to A549 cells was 59.12%; The apoptosis rate and cycle blockage rate of A549 cell induced by 131I-1H12 were in a dose-effect relationship; The supreme apoptosis rate (44.35±3.31)% and G2/M cell cycle blockage rate (51.17±2.98)% were found in the A549 cells treated with 148kBq 131I-1H12. Conclusion 131I-1H12 can immunobinding with A549 cells and regulate cell cycle and induce apoptosis of A549 cells to inhibit its proliferation; It might have some potential application prospect in biological targeted diagnosis and therapeutics.