This study was carried out to investigate the effects of dietary restriction on mobilization of Mongolia ovine maternal reserves and their fetal growth during late gestation. Thirty five Mongolia ewes mated at a synchronized estrus were selected. Six ewes were slaughtered at 90 days of gestation and the remained ewes were allocated to three groups: ad libitum group [group C, average daily ME intake=0.670 MJ/(kg W^0.75·d), n=8], restricted group 1 [group R1, average daily ME intake=0.175 MJ/(kg W^0.75·d), n=12] and restricted group 2 [group R2, average daily ME intake=0.330 MJ/(kg W^0.75·d), n=9]. At 140 days of gestation, six ewes in each group were slaughtered. The results showed as follows: at 140 days of gestation, maternal net body weight (BW) lose, carcass weight, dry matter, ether extract, crude protein and ash in meat, as while as the concentrations of glucose (GLU) and total amino acid (TAA) in plasma of ewes in group R1 were significantly lower than those in group C (P<0.01), but the concentrations of non-esterified fatty acid (NEFA) and β-hydroxybutyric acid (BHBA) in plasma were significantly higher than those in group C (P<0.01); compared with group C, maternal net BW lose, carcass weight, dry matter and ether extract in meat, as while as the concentrations of GLU and TAA in plasma of ewes in group R2 were significantly decreased (P<0.01), and plasma NEFA concentration was significantly increased (P<0.01). The maternal BW lose led to significant reductions of fetal weight both in groups R1 and R2 (P<0.01), and body length (P<0.05), thoracic girth (P<0.05), abdomen circumference (P<0.05) and curved crown-rump length (P<0.01) in group R1. In conclusion, with the decrease of dietary nutrient level during late gestation, the maternal protective buffer system is still playing major roles when average daily ME intake=0.330 MJ/(kg W^0.75·d), but the system may be destroyed when average daily ME intake=0.175 MJ/(kg W^0.75·d), which results in serious impacts on fetal growth and development.