Objective  To observe the change in the number and function of endothelial progenitor cells （EPCs） from bone marrow in rats with diabetic retinopathy （DR）； to discuss the role of EPCs in the pathogenesis of DR. Methods  In an experimental study， 50 male Wistar rats were divided into a control （CON） group （14 rats） and diabetes （DM） group （36 rats）. The rats in the DM were further divided into 3 groups of 12 rats each based on the time periods when analysis was performed： 1 month （DM1）， 3 months （DM3） and 6 months （DM6）. Mononuclear cells were collected by density gradient centrifugation from the bone marrow of the rats. The isolated cells were cultivated in dishes coated with fibronectin. Immunofluorescence staining and flow cytometry were used to identify EPCs. The number of EPCs in the colony was assayed by CFU counting； proliferation， migration and adhesion function of EPCs were assayed by MTT chromatometry， modified Boyden chamber assay and adhesion activity assay. All eyeballs were examined by hematoxylin and eosin （HE） staining and vascular endothelial growth factor （VEGF） by immunity set expression. The correlation between changes in EPCs and DR morphological changes was analyzed. The changes in the number and function of EPCs from bone marrow and expression of VEGF in the retina were analyzed by single factor analysis of variance and LSD-t test. Results  The number of cell clusters in bone marrow-derived EPCs was significantly reduced in the DM1， DM3， DM6 groups （9.6±1.8， 11.5±2.5， 14.0±2.4 n/×200 fields） compared to the CON group （16.6±2.7 n/×200 fields）. The ability of EPCs to proliferate was reduced in the DM1， DM3， DM6 groups （0.133±0.027， 0.106±0.016， 0.072±0.011 OD） compared to the CON group （0.203±0.068 OD）. The ability of EPCs to migrate was reduced in the DM1， DM3， DM6 groups （11.9±2.2， 10.1±1.8， 8.9±1.2 n/×200 fields） compared to the CON group （17.9±4.8 n/×200 fields）. The adhesion ability of EPCs was reduced in the DM1， DM3， DM6 groups （14.8±3.2， 10.5±2.0， 7.5±1.2 n/×200 fields） compared to the CON group （17.9±4.8 n/×200 fields）. Accompanied by responsive pathological changes of retinal structure and vessels， the thickness of the retina was reduced and retinal cells became disorganized in the DM1 and DM3 groups. Endothelial cells expressed edema in the DM6 group. The expression of VEGF in the retina of rats was 0， 18.6%±2.74%， 34.3%±2.21%， 58.73±2.48%， in CON， DM1， DM3， DM6 groups respectively. Conclusion  The number and biological dysfunction of EPCs from bone marrow were reduced in diabetic rats. With the development of DR， the number of EPCs increased gradually.