Aim To investigate the effect of over-taking methionine on endothelial progenitor cells (EPC) in rabbit peripheral blood and the intervention of granulocyto-colony stimulating factor (G-CSF) in the process. Methods Newsland rabbits were divided into four groups: normal control, G-CSF, homocysteine (HCY), HCY+G-CSF groups. Normal and G-CSF groups were fed with normal food, HCY and HCY+G-CSF groups with 1% methionine food. The animals in G-CSF and HCY+G-CSF groups were injected with G-CSF 50 μg/d by belly cavity. EPC number in peripheral blood were surveyed at 1st, 2nd, 3rd, 4th, 8th, 12th week and serum nitric oxide (NO), HCY were also measured at 12th week. Results EPC in nomal control group had been low level basal line; EPC in G-CSF group had kept highest in the whole period; EPC in HCY group seemed descending at 1st, 2nd, 3rd, 4th week, and ascending at 8th, 12th week; EPC in HCY+G-CSF group decreased gradually, which was between that of G-CSF and normal control group. Compared with normal control group, EPC in HCY+G-CSF group was higher during the former two weeks. EPC in HCY+G-CSF group was lower than that in G-CSF group since 2nd week (p<0.01). At 12th week serum NO in HCY group was lower than that in HCY+G-CSF group (p<0.05), and serum NO were equal among normal control, G-CSF , and HCY+G-CSF groups. Serum HCY increased only in methionine food groups. Conclusion HCY reduced EPC in the beginning and hightened it later, descended serum NO which could been attenuated by G-CSF. G-CSF improved endothelium dysfunction caused by HCY, and the effect possibly related to mobilization of G-CSF to EPC.