Objective To investigate the relationship between serum thrombin-antithrombin Ⅲ complex(TAT)and soluble fms-like tyrosine kinase-1(sFlt-1)levels and the progression and prognosis of sepsis pa-tients.Methods A total of 117 patients with sepsis admitted to the hospital from January 2021 to May 2023 were selected as the observation group,and 42 healthy volunteers in the hospital during the same period were selected as the control group.Patients with sepsis were divided into ordinary sepsis group(60 cases)and sep-tic shock group(57 cases).The observation group was divided into death group and survival group according to the prognosis after 90 days of treatment.Serum TAT and sFlt-1 levels were detected by enzyme-linked im-munosorbent assay.Logistic regression was used to analyze the death influencing factors of sepsis patients,and a prognostic prediction model of sepsis patients based on TAT and sFlt-1 was established.The predictive value of receiver operating characteristics(ROC)curve analysis indexes for the death of sepsis patients was evalua-ted.Results The levels of TAT[(12.59±5.35)ng/mL]and sFlt-1[(28.58±4.05)ng/mL]in the observa-tion group were higher than those in the control group[(2.65±0.88)ng/mL and(16.50±3.60)ng/mL,re-spectively].The difference was statistically significant(t=19.386,17.065,P＜0.001).The serum TAT[(15.09±4.99)ng/mL]and sFlt-1[(30.45±3.30)ng/mL]levels in septic shock group were higher than those in ordinary sepsis group[(10.22±4.57)ng/mL and(26.81±3.92)ng/mL,respectively].The differ-ence was statistically significant(t=5.503,5.429,P＜0.001).The proportion of septic shock,sequential or-gan failure assessment(SOFA)score,acute physiological and chronic health evaluation Ⅱ(APACHE Ⅱ)score,blood lactate,procalcitonin,TAT and sFlt-1 levels in the death group were higher than those in the sur-vival group,with statistical significance(P＜0.05).Sepsis shock,increased SOFA score,increased APACHEⅡ score and increased blood lactic acid,TAT and sFlt-1 were independent risk factors for death in sepsis pa-tients(P＜0.05).ROC curve analysis showed that the area under the curve(AUC)of the predictive model for predicting death in sepsis patients was 0.947,which was higher than the AUC predicted by disease degree,SOFA score,APACHE Ⅱ score,blood lactic acid,TAT,and sFlt-1 alone(Z=6.525,4.414,4.835,3.787,3.956,3.507,P＜0.001).Conclusion The increase of serum TAT and sFlt-1 levels in patients with sepsis is closely related to disease progression and poor prognosis,and the prediction model established based on TAT and sFlt-1 has high predictive value for the death of patients with sepsis.