【Objective】 To research the effect of the Fc, Fab and F(ab′)2 fragments of immunoglobulin G, the main components of Human Immunoglobulin(pH4) for Intravenous Injection(IVIG), on the phagocytic function of macrophages derived from THP-1 cells. 【Methods】 First of all, IVIG was digested with papain and pepsin to obtain Fc, Fab and F(ab′)2, and these components were then identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Afterwards, propylene glycol monomethyl ether acetate (PMA) was used to induce THP-1 cells to differentiate into M0 macrophages. Finally, the sensitized erythrocytes were labeled with carboxy fluorescein succinimidyl ester (CFSE), and the effect of the above components on the phagocytic ability of M0 macrophages to engulf sensitized erythrocytes was detected by flow cytometry. 【Results】 The identification results of SDS-PAGE showed that the prepared IgG fragments met the requirements of subsequent experiments. Flow cytometry performs showed that the phagocytosis model of M0 macrophages had been successfully established. When the concentration of Fc increased from 0.1μg/ mL to 10μg/ mL, the phagocytosis rate of erythrocytes sensitized by M0 macrophages decreased from (24.21±0.58) % to (12.27±0.19) %. When the concentration of IVIG protein increased from 0.1 μg/ml to 10 μg/ml, the phagocytosis rate decreased from (20.57±0.39) % to (0.20±0.03) %. Meanwhile, at the same protein concentration (10 μg/ml), the inhibitory effect of Fc on phagocytosis was only half that of IVIG. In addition, Fab, F(ab′)2, and human serum albumin could not inhibit phagocytosis of M0 macrophages. 【Conclusion】 IVIG can effectively inhibit the phagocytosis of THP-1 derived M0 macrophages, which is mainly dependent on the Fc, but not related to the Fab of IgG and F (ab′)2.