Objective To discuss the curative effect of unremitting pump infusion of microdose urokinase(100 000 u/24 h)into the cerebral venous sinus in treating thrombosis in cerebral venous sinus which had anatomical variation. Methods Mechanical disruption of the thrombus and unremitting pump infusion of microdose urokinase(100 000 u/24 h)into the cerebral venous sinus for 48-96 hours were employed in 9 patients with thrombosis in anatomically varied cerebral venous sinus.After the procedure the original disorder was actively treated and the anticoagulant therapy was continued for 6 months.A follow-up of 6-12 months(mean 10 months) was conducted. Results Recanalization of the previously occluded cerebral venous sinus was obtained in all 9 patients.The dose of urokinase was 100 000 u/24 h in 8 patients.For the remaining one patient the dose of urokinase was 100 000 u/24 h in the first 48 hours,then the dose Was increased to 250 000u/24 h. Excellent result was obtained in all patients.Conclusion Unremitting pump infusion of microdose urokinase into the cerebral venous sinus can effectively treat the thrombosis in anatomically varied cerebral venous sinus.