In the present study, the system of nonradioactive iodine-labeled-antibodies linking inductively coupled plasma mass spectrometry for immunoassaywas reported. The goat-anti-Escherichia coli and goat anti rabbit were consideredas simulant antigen and antibody respectively in order to establish a new methodof immunoassay by inductively coupled plasma mass spectrometry which has theadvantage of high sensitivity, low detection limit and preferable linearityrange. During the experiment, the N-bromosuccinimide, a mild oxidant, was used tooxidize the non-radioactive iodine (127I) that labeled the protein. The method ofnonradioactive iodine labeled protein was established and the best labelingcondition was explored. The compound of I was purified by Sephadex G50 columnchromatography, then the stability and activity were examined. The results showedthat the labeling program was simple, reaction time was within two minutes, thelabeling yield achieved 63.12% and none of I shed from the compound after 96hours. The simulant antigen and antibody reacted on polystyrene microtiter plateand the I was detected by ICP-MS, the detection limit of the method was 0.12 mg?L-1, relative standard deviation (n=9) was less than 3% and the linearlydependent coefficient was 0.998 7. This system can also be used in analysis ofother protein, nucleic acid and so on.环境保护及节能减排专项项目资助