The study was conducted to investigate the effect of nano selenium on feed utilization of ration containing a high ratio of wheat bran. Fifteen Awassi ewes were used with an average body weight of 51.58 ± 1.71 kg and age ranged between 3-4 years. The ewes were distributed into three groups, five in each. Through the study that lasted 72 days, ewes were fed with a restricted amount of feed, 1.5 kg of dry matter per day. The first group (control) was fed a diet high in barley grains with an optimal ratio of wheat bran (17%), while ewes in the second and third groups were fed with diets higher in wheat bran (37%) with a dosage 0.3 mg nano-selenium/ewe for ewes in third group. The results indicated that increasing the wheat bran ratio in the ewe diet led to a significant decrease (P≤0.05) in milk production in the second group 301.71 g/day, as compared to the control 390 g/day. The addition of selenium led to an improve milk production which reached to 455.15 g with a difference of 16.71%, as compared to the control. In general, milk composition of fat, protein, lactose, and solid non-fat were not affected significantly by treatments. However, the somatic cell count was significantly lower in the second period of the study in the second and third groups as compared to the control.