This study aimed to elucidate the effects of dietary calcium (Ca) level on nitrogen balance and emission of nitrogen and phosphorus of Yunnan semi-fine wool sheep in mid and late gestations, for providing theoretical guidance of Ca supplementation in the diet of Yunnan semi-fine wool sheep from the perspective of environmental protection. Fifty multiparous sheep in good body condition and with similar body weight and breeding date were randomly blocked to 5 groups with 10 sheep in each group. Sheep in the 5 groups were fed diets with varying Ca levels which were 0.42%, 0.45%, 0.56%, 0.65% and 0.82% in mid gestation, and 0.40%, 0.50%, 0.60%, 0.69% and 0.87% in late gestation, respectively. The experiment lasted for 104 days, with the first 14 d as the preliminary period and the following 90 d as the formal period. Five sheep from each group were selected in mid and late gestations for digestion and metabolism trial, and the digestion and metabolism trial lasted for 5 days. The results showed that nitrogen retention and nitrogen retention rate in mid gestation in 0.82% group were significantly higher than those in 0.56% group (P<0.05), but did not differ significantly among other groups (P>0.05). Nitrogen retention in late gestation in 0.69% and 0.87% groups were significantly higher than that in other groups (P<0.01), and no significant difference among other groups (P>0.05). The nitrogen retention rate in late gestation in 0.69% and 0.87% groups was significantly higher than that in 0.50% group (P<0.01), and was significantly higher than that in 0.40% and 0.60% groups (P<0.05), but there were no significant differences among other groups (P>0.05). Nitrogen balance in all the groups was in positive in mid and late gestations. Fecal dry matter emission was the lowest in 0.65% group in mid gestation, and it was not significantly affected by dietary Ca level in late gestation (P>0.05). The urine emission in 0.56% group in mid gestation and in 0.40% group in late gestation was significantly higher than that in other groups (P<0.01), but no significant differences were found in urine emission among other groups (P>0.05). However, total nitrogen emission and total phosphorus emission in mid gestation had no significant changes with the increase of dietary Ca level (P>0.05). In late gestation, the total nitrogen emission did not affect by dietary Ca level (P>0.05), but the total phosphorus emission in late gestation in 0.87% group was significantly lower than that in other groups (P<0.05). In conclusion, under the conditions of this experiment, dietary calcium level significantly affects the nitrogen deposition and nitrogen deposition rate in mid and late gestations of Yunnan semi-fine wool sheep, which in 0.82% group are the highest in mid gestation, and in 0.69% group and 0.87% group are higher in late gestation. Dietary calcium level has no significant effects on total nitrogen emission in mid and late gestations and total phosphorus emission in mid gestation of Yunnan semi-fine wool sheep.