Aim To detect the development of monocytes(Ly6G^－CD11b^＋Ly6C^hi and Ly6G^－CD11b^＋Ly6C^lo)and proliferating macrophage in atherosclerosis of ApoE^―/― mice. Methods We randomly assigned 40 ApoE^－/－ mice into high-fat diet or normal chow diet group, which were sacrificed at the end of weeks 2, 4, 6 and 8. Lipids of aortic sinus were stained with oil red O. The macrophage and proliferating macrophage(F4/80 and Ki67 double positive cells)in plaque were detected by immunofluorescence staining and confocal microscopy. Flow cytometry methods were used to analyze the proportions of circulationg monocyte subsets. Results In the formation progress of atherosclerosis, aortic atherosclerosis gradually aggravated with high-fat diet over time. The total macrophages and proliferation macrophage density showed an increasing trend before the first four weeks with high-fat diet, which reached a peak at the fourth week. Before the first six weeks with high-fat diet, the percentage of proliferating macrophage and macrophages density were gradually increased and reached a peak at the sixth week. The proportions of cycle Ly6C^hi monocyte was increased with high-fat diet time passing. Conclusions In the development progress of atherosclerosis model, the proportions of circulating Ly6G^－CD11b^＋Ly6C^hi monocyte subsets gradually aggravated with high-fat diet time passing and the increasing is consistent. Proliferating macrophage density reached a plateau at the first four weeks.