Abstract: Objective To investigate the effect of adipose-derived mesenchymal stem cell (ADSC) on macrophage polarization and macrophage phagocytosis of apoptotic neutrophils. Methods Rat ADSC, macrophages and neutrophils were isolated, cultured, and identified. neutrophils were labeled with CFSE fluorescent dye. Cells were co-cultured accordingly: macrophage, macrophage+ADSC, macrophage+ADSC supernatant, macrophage+neutrophil, macrophage+ADSC+neutrophil, macrophage+ADSC supernatant+neutrophil. Polarization and phagocytosis were measured using immunofluorescence staining and flow cymetory analysis. Results Compared with macrophage group, percentage of CD163⁺cells increased significantly in macrophage+ADSC group and macrophage+ADSC supernatant group. Compared with macrophage+neutrophil group, percentages of CD163⁺cells and CFSE⁺CD163⁺cells significantly increased in macrophage+ADSC+neutrophil group and macrophage+ADSC supernatant+neutrophil group. Conclusion ADSC facilitates macrophage phagocytosis of apoptotic neutrophils through turning macrophages into M2c type.