The present experiment was conducted to determine nutritional values of Wild pistachio trees (P. khinjuk) leaves it's use it in the diet of sheep. Initially chemical composition of P. khinjuk leaf was determined. The diets containing 0, 5, 10, 15, 20, 25 and 30% of P. khinjuk leaf were prepared and used for sheep to determine the best replacement level of it with corn silage. Fermentation and digestion characteristics of experimental diets were investigated by in vitro gas production technique. Effects of selected diets from the in vitro step (control and diet contains 30% of the khinjuk leaf) on feed intake, digestibility of nutrients, ruminal fermentation parameters and blood metabolites were studied using 10 Arabian rams in a completely randomized design. The concentration of crude protein, NDF, ADF and tannin in khinjuk leaf were 9.88, 47.95, 39.02 and 3.9%, respectively. The gas production declined by increasing the percentage of P. khinjuk leaf in the diet, but the microbial biomass and efficiency of microbial synthesis was increased (P<0.05). Dry matter intake was increased in sheep fed diets containing P. khinjuk leaf. There was no significant difference for apparent digestibility of dry matter, NDF, ADF, and blood glucose and cholesterol among experimental diets (P>0.05). Digestibility of crude protein and concentration of ammonia nitrogen in rumen fluid and blood urea nitrogen in diet containing of P. khinjuk leaf was lower (P<0.05). Therefore, dietary inclusion of P. khinjuk leaf up to 30% in the diets of sheep had no negative effect on digestibility, ruminal and blood parameters of sheep.