Abstract: Objective To explore the therapeutic effect of partial splenic embolization of different embolized volumes for idiopathic thrombocytopenic purpura (ITP) and consequent changes of the splenic function. Methods Forty-five ITP patients were randomized into 2 groups to receive splenic embolization with gelatin sponge particles, and the embolized volume ranged between 60% and 80% in the former group (group A), and between 40% and 60% in the latter group (group B). Results The platelet counts of the patients in both groups markedly increased one week after the operation, and the average count was significant higher in group A than in group B one year after the operation (P<0.01). The splenic function of the patients in neither of groups underwent any significant changes after the operation (P>0.05). Conclusion Splenic embolization of different volumes produces similar therapeutic effect on ITP, but more extensive embolization may insure long-lasting effect with better safety and less influence on splenic function.