Objective: To study the change of antibody level in 18 patients with immune thrombocytopenia (ITP) after infusion Human i.v. Ig (IVIG) and investigate the effect of IVIG on antibody level of patients.Methods: From Jan. 2016 to July 2017 in 12 hospitals, 18 cases of ITP patients as the research object, used the ELISA method to detect the change of five items of hepatitis B virus, hepatitis C virus antibody, syphilis antibody and HIV antibody level in these patients with infusion of IVIG before and after IVIG infusion for 14 to 28 days, 80 to 90 days; if the antibody level was pos. used nucleic acid detection technol. to confirm by further.Results: 18 cases of patients with infusion of IVIG for 14 days, the anti-HBs titers were significantly increased; after infusion of IVIG 90 days, anti-HBs titers decreased, but it was still at a high level compared with that before infusion.Only a few patients can recover to the level before infusion, which showed that the metabolic ability of patients to the passive transfer of anti-HBs was obvious difference.Conclusion: High doses infusion of IVIG in the short term may increase the antibody level in patients with ITP, suggesting that it is important to exclude the passive transfer of antibodies in patients undergoing IVIG infusion.