Abstract：Objective To establish a quantitative chemiluminescence immunoassay for triiodothyronine in human serum. Methods Competing method and the microplate coating technology was used in the assay. Anti-T3 antibody coated on the 96 microtiter plate, T3 labeled horse radish peroxidase，luminol and hydrogen peroxide were used as Luminescent substrate to establish the assay. Results The linear range of the assay was 0.5-8.0 ng/mL．The sensitivity of assay was 0.18 ng/mL．The coefficients of variation for intra-assay were 4.4％-6.6％，and for inter-assay were 5.5％-10.6％ respectively．The recovery rate of the samples was 90．0％-113．3％．The correlation coefficient was 0.9922 after serial dilutions of the high concentration sample. The cross-reactivity rate of thyronine and 3,3',5'-triiodothyronine (rT3) with triiodothyronine was 0.35％ and 0.54％ respectively．The examination result of the assay was correlated well with the Roche ECLIA. Conclusion The chemiluminescence immunoassay for triiodothyronine established in this study is sensitive, specific and convenient. It might be suitable for clinical and research application