A　new　chemiluminescent　reagent　isothiocyanato-isoluminol　(ITCI)　was　used　to　label　Anti-AFP,　The　molar　incorporation　ratios　are　estimated　to　be　0.25　similar　to　0.50　mole　of　ITCI　per　mole　Anti-AFP,　The　results　show　that　there　are　no　apparent　changes　in　the　immunoreactivity　of　the　labeled　Anti-AFP　and　the　quantum　efficiency　of　ITCI　attached　to　the　Anti-AFP,　In　addition,　the　conditions　of　labeling　reaction,　sandwich　immunoassay　and　electro-chemiluminescent　reaction　were　studied.　Morever,　a　new　sandwich　electrochemiluminescence　immunoassay(ECLIA)　is　firstly　established,　and　used　to　detect　AFP　in　human　serum.　The　calibration　ranges　is　5.0　similar　to　100.0　ng/mL　and　the　minimal　detection　concentration　is　2.0　ng/　mL.