The social amoeba Dictyostelium discoideum is increasingly being used as a simple model for the investigation of problems that are relevant to development and pathogenesis.The investigation of autofluorescence during development is helpful to identifying basic fluorescent threshold,accuracy of experiment marked with fluorescent dye,and cellular sorting with flow cytometry.The autofluorescence of KAx-3 cells at different developmental phases was observed with fluorescent microscope in wild type D.discoideum.The results showed that the autofluorescence of spore capsule at fruiting body was strongest,while the autofluorescence was weakest at unicellular phase under excitement of wide blue (abbr: WB).There was no autofluorescence at slug under excitement of wide green (abbr: WG) and wide interference yellow (abbr: WIY).The autofluorescence at unicellular phase was weakest under excitement of wide ultraviolet ray (abbr: WU).The autofluorescent intensity was changed during development.Green,red,and blue colors of autofluorescences were separately excited by WB,WG and WIY,and WU.The results indicate the diversity autofluorescence spectrum of KAx-3 cells in wild type D.discoideum.