Abstract: The objective of this study was to evaluate the effects of L-arginine infusion through jugular vein on growth and development of Ordos Fine-wool Sheep fetuses during late gestation. Twenty-two ewes received an i.v.bolus of either 115μmol/（kg·BW） of Arg-HCl（Arg1 group） or 155 μmol/（kg·BW） of Arg-HCl（Arg2 group） or saline solution（control group） 3times per day from 90 to 140 days post-pregnancy. On the days 115 and 140 of pregnancy, the ewes were physically examined;The body weight, organ weight and body length of their fetuses were recorded; The concentrations of amino acids in plasma of ewes and fetuses were determined. The results revealed that on the day 140 of pregnancy, the heart weight and liver weight of fetuses in Arg2 group were significantly increased compared with those of fetuses in Arg1 group and control group（P〈0.05）. On the days115 and 140 of pregnancy, the plasma concentrations of arginine and ornithine of ewes received systematic L-arginine infusion were significantly increased（P ≤0.01）, and the plasma concentrations of glucogenic amino acid of their fetuses, including threonine, methionine, phenylalanine and lysine, were also significantly increased（P≤0.05）.