Abstract： Objective To evaluate the efficacy of intra-arterial hrombolytic therapy in patients with acute ischemic stroke having their time window over 3 h and analyze its influencing factors.Methods Sixteen patients with acute ischemic stroke having their time window over 3 h, admitted to Department of Neuroradiology of Central Hospital of Nancy University from January 2008 to January 2009, were treated by intra-arterial thrombolysis using chemical (rt-PA) and mechanical technique. These patients had carotid stroke for less than 3 h, vertebrobasilar stroke for less than 24 h or coma for less than 6 h. According to the images of DSA, the recanalization after thrombolysis was evaluated by thrombolysis in cerebral infarction (TICI) grades. CT scans 24 h after thrombolysis were operated to detect the hemorrhage complications. NIHSS at baseline and 24 h after thrombolysis and modified Rankin Scale (mRS) were recorded to evaluate the clinical efficacy. Results After intra-arterial thrombolysis, 7 (43.75%) in 16 patients got totally recanalization (TICI grade 3), another 7 partial recanalization (TICI grade 2), and the left 2 patients failed in recanalization (TICI grade 1); the total recanalization rate was 87.5%. A significant reduction of NIHSS scores after the thrombolysis was noted as compared with that before the thrombolysis. The atients with occlusion of anterior ciculation having time window over 5 h enjoyed no reduction of NIHSS scores after thrombolysis; mRS scores in patients having time window over 5 h were ignificantly higher as compared with those in patients having time window less than 5 h.The patients having ICA occlusion (n=5) had no reduction of NIHSS scores after thrombolysis, and enjoyed poorer prognosis as compared with whose occlusion lay in the middle cerebral artery (MCA,n=9) and basilar artery (BA, n=2). By CT scan 24 h after thrombolysis, 4 patients were detected with symptomatic intra cerebral hemorrhage (ICH, 25%) and all of them with occlusion in the internal carotid artery system: 1 patient with occlusion in MCA died of cerebral hernia causing by the large hematoma;the other 3 were all occlusion in ICA. Although reocclusion after thrombolysis occurred, 1 patient was benefitted from the affluent collateral perfusion and got a good prognosis. Conclusion For patientswith BA and MCA occlusion having time window over 3 h, intra-arterial thrombolytic therapy is effective and selective resulting from their high recanalization rate, improvement of neurological function and clinical end. The therapy should be individually chosen; mutiple factors as time window of stroke,location of stroke, ompensatory circulation and complications should be considered in evaluating the efficacy; and the hemorrhage complications should be avoided.