Objective To evaluate the safety and effectiveness of interventional therapy for hyperthyroidism. Methods From 1995 to 2000, 38 cases underwent bilateral super-selective superior thyroid arteries embolization with brown-algae microballs.Results There was no misembolization and mortality. Hyperthyroidism crisis developed in 2 cases. Thirty eight cases were followed-up for 0.5～5 years (the median time was 2.2 years). Medications were needed only in one patient because of relapse and the others were cured. Conclusion This procedure features miniinvasive trauma, less complications and quick recovery. It may be a safe and rational treatment for hyperthyroidism.