Thrombin-antithrombin complex (TAT) is the product of coagulation and anticoagulation balance. Its detection reflects thrombin status and can be used as an auxiliary in the diagnosis of thrombotic diseases. A chemiluminescence immunoassay method was established to analyze TAT in human plasma samples, and its analytical performance was evaluated. The TAT was used as immunogen for monoclonal antibody preparation. TAT measurement method was established using double antibody sandwich format. After the optimization of reaction, the bulk reagent concentrations of magnetic microparticle coated with antibody and acridinium labeled antibody were 0.20 g/L and 0.2 mg/L, respectively, and the sample size was 50 μL. The reaction of magnetic particle coated antibody and sample were incubated for 5 min at 37 ℃, and 5 min for subsequent reacting with the antibody labeled with acridinium. There was no cross-reaction with samples containing 0.20 mg/mL prothrombin or 0.31 mg/mL antithrombin Ⅲ. Besides, there was a high correlation (r＞0.95) between this method and TAT test kit of Sysmex. LoB is less than or equal to 0.20 ng/mL. LoD is less than or equal to 0.40 ng/mL. The linear correlation coefficient is 0.998 in the detection interval of 0.40 to 120 ng/mL, and the accuracy is within the range of ±8%. A quantitative chemiluminescence immunoassay method for TAT measurement has been established, and the performance meets customer needs for clinical utility.