The interaction between pathogenic microbes and host cells is crucial for studies on infections and tumor cell biology. The kinetic studies of cell cycle are of significance for understanding the mechanisms mediated by microbes versus host cells. In this paper, a novel method for cell cycle analysis in mouse splenic cells by Ki67 and 4′，6-diamidino-2-phenylindole (DAPI) or propidium iodide (PI) co-staining is introduced.