Objective：To study the method and effect of  thrombolytic therapy for deep venous thrombosis (DVT).
Methods：We performed a retrospective analysis of the clinical data of 146 DVT cases,which were grouped into acute (0-7 d, n=40), sub-acute  (8-30 d, n=70) and chronic  (>3 d, n=36) series according to their course of disease. Statistical analysis was used to analyze the data including femoral vein peek velocity/diameter changes, popliteal vein peek velocity/diameter changes and circumference changes in the thigh and calf before and after treatment.
Results：Femoral and popliteal vein peek velocity increased after thrombolytic therapy.  On the other hand, femoral and popliteal vein diameter, along with circumference in the thigh and calf, decreased after thrombolytic therapy, with the highest decrease in acute group and lowest decrease in chronic group.
Conclusions：As regards thrombolytic therapy, the earlier it is performed, the better will be the effects achieved. Aggressive thrombolytic therapy can improve venous obstruction and valve damage, and attenuate postthrombotic syndrome.