This study was carried out to investigate the effects of maternal undernutrition during late pregnancy on growth development and physiological and biochemical indexes in blood of Mongolia ovine fetus. A total of 42 healthy Mongolia ewes mated at a synchronized estrus were selected. Six ewes were slaughtered at the beginning of the experiment (90 d of gestation) and the remained animals were allocated to three metabolizable energy (ME) level groups: restricted group 1 [RG1, 0.175 MJ/(kg BW^0.75·d), n=14], restricted group 2 [RG2, 0.330 MJ/(kg BW^0.75·d), n=12] and control group [CG, ad libitum, 0.670 MJ/(kg BW^0.75·d), n=10]. At 140 d of gestation, six ewes in each group were slaughtered, quickly removed the fetus, and measured the fetal body weight, body measurements, physiological and biochemical indexes in blood. The results showed as follows: fetal weight (P<0.01), body length (P<0.05), chest circumference (P<0.05), abdominal circumference (P<0.05), curved crown-rump length (P<0.01), red blood cell count (P<0.01), hemoglobin content (P<0.01), hematokrit (P<0.01), total amino acid content (P<0.05), total antioxidation capacity (P<0.01) and superoxide dismutase activity (P<0.05) were significantly decreased and average platelet volume (P<0.05), coefficient of variation of red blood cell distribution width (P<0.05), nonesterified fatty acid content (P<0.05), β-hydroxybutyrate content (P<0.01), glutathione peroxidase activity (P<0.05) and malonaldehyde content (P<0.05) were significantly enhanced in RG1 compared with CG. For RG2, the decrease of fetal body weight (P<0.01) and total antioxidation capacity (P<0.05) was founded and average platelet volume was increased compared with CG (P<0.05). In conclusion, the fetal growth and development are affected seriously by maternal undernutrition during late pregnancy, which leads to severe malnourished anaemia, nutritional and metabolic disorder, and oxidative stress of fetus in RG1.