Abstract: Objective:To evaluate the efficacy and safety of modified plasma exchange in the treatment of adult patients with severe immune thrombocytopenic purpura(ITP).Method:One hundred and sixteen patients with severe ITP were randomly divided into different treatment groups.Forty-three cases of severe ITP patients were treated with modified plasma exchange combined with glucocorticoid(group A).Thirty-seven patients were treated with traditional plasma exchange combined with glucocorticoid(group B).Thirty-four patients were treated only with glucocorticoid(group C).Before and after treatment,platelet associated immunoglobulin,platelet count,coagulation function and plasma protein level were detected in each group,then statistical analysis was taken.Adverse reactions were recorded in each group during the treatment period,and comparative analysis was done.Result:Compared with group C,platelet associated immunoglobulin levels in group A and B decreased more lower,and the platelet counts were increased more quickly,the difference were statistically significant.There was significant differences between the group A and B in the rise speed of platelet count,and also in the level of platelet associated immunoglobulin,group A was better than group B.Before and after treatment,the difference was not statistically significant between three groups in the clotting time,plasma albumin and fibrinogen levels.The incidence of edema,dizziness and fatigue in group A was higher than those in the group B within 24 hours after replacement,but the incidence rate of allergic reaction and fever reaction was significantly lower than those in group B.Conclusion:The treatment of group A had a considerable effect.The effect was better than that of group B and C.Severe adverse reactions such as allergic reactions and fever in group A were significantly lower than those in group B.Modified plasma exchange could save the plasma.But the occurrence of low plasma protein,especially low serum albumin,should be actively prevented.