Objective:To examine longitudinal associations between dynamic changes in anticoagulant protein(AT,PC,PS)activity and anticoagulation efficacy in lower extremity deep vein thrombosis(DVT)patients.Methods:220 DVT patients received standard LMWH-warfarin therapy.Serial measurements of AT,PC,PS activity and imaging parameters(thrombus volume,venous obstruction rate,collateral circulation,venous wall thickness,blood flow velocity)were taken at baseline(T0),1 week(T1),1 month(T2),and 3 months(T3).Associations were analyzed using linear mixed models(LMM)and Cox regres-sion.Results:Patients were stratified by 3-month efficacy:ineffective(n=31)and effective(n=189)groups.The effective group had lower age,treatment delay,hereditary thrombophilia family history,and ≥2 comorbidities(P＜0.05).In the effec-tive group,the activities of AT,PC,PS demonstrated continuous increases from T1 to T3,reaching peak levels at T3(P＜0.05),whereas no significant changes in activity were observed at any time point in the ineffective group(P＞0.05).At the T1 assessment,no statistically significant differences were found in imaging indices between the two groups(P＞0.05).During the T1,to T3 period,the effective group showed continuous declines in thrombus volume,venous obstruction rate,and ve-nous wall thickness(P＜0.001),accompanied by parallel improvements in collateral circulation grading and blood flow velocity(P＜0.001).In contrast,the ineffective group exhibited no significant changes in imaging indices during T1 to T3(P＞0.05).LMM revealed significant positive associations between combined AT,PC,PS exposure and efficacy(P＜0.05).Cox regression identified AT≤70％,PC≤65％,and PS≤55％as independent predictors of poor efficacy(P＜0.05).Conclusion:Dynamic AT,PC,PS monitoring predicts anticoagulation efficacy early.Insufficient activity recovery correlates with delayed thrombus regres-sion,guiding individualized therapy.