Abstract: Fourteen ewes of Gansu meat sheep new breeding population were selected to study the milk yield and nutrient composition during 30 days postpartum in this paper. The results showed that the ewes of Gansu meat sheep new breed population had higher lactation performance within 30 days postpartum. The 30 days’ total milk yield was (32.82±0.19) kg, and daily average daily milk yield was (1.09±0.08) kg. The lactation curve equation of 1-30 days was Y=530.60t^0.368e^-0.015t, while daily weight gain reached (0.234±0.033) kg. The milk conventional components and physical properties had significant changes in the first postnatal day, and tended to be steady until the third day. The milk composition differ between colostrums and normal milk, and had certain regularly changes. The content of milk soluble solids, non fat solids, protein and fat decreased, while lactose showed upward trend from the first day to 7th day. The content of milk protein, non fat solids, density and acidity showed a decreasing trend from the first day to 21th day, then rose in the following days. The content of milk fat, soluble solids and acidity had been on a downward trend. while the lactose had upward trend from the first day to 14th day, then its content tends to be steady. The freezing point showed increasing trend from the first day to 5th day, then decreased slowly. The density had no significant changes within 30 days postpartum (P>0.05). The above results have provided the basic data for Gansu meat sheep new breed population’s characteristics and the supplementary feeding of early weaned lambs.