Abstract: Six Gansu alpine sheep with 28 kg in average weight and fitted with permanent rumen fistula were chosen to investigate the nutritional evaluation of sunflower straw and plate on sheep in a 3×3 Latin square design. 1) On an air dry basis, dry matter, crude protein, ether extract, crude fiber, neutral detergent fiber, acid detergent fiber, calcium, phosphorus were 90.73%, 5.72%, 0.89%, 30.15%, 53.09%, 39.40%, 11.61%, 0.84%, 0.13% respectively in sunflower straw and 89.63%, 11.84%, 2.13%, 12.48%, 23.51%, 15.41%, 14.04%, 0.97%, 0.29% in sunflower plate. 2) The digestibility of dry matter ,nitrogen, organic matter, neutral detergent fiber, acid detergent fiber, calcium, phosphorus were 61.61%, 65.37%, 65.19%, 48.18%, 44.89%, 29.10%, 26.07% respectively in sunflower straw and 70.96%, 69.57%, 76.26%, 60.87%, 58.60%, 37.98%, 44.75% in sunflower plate. The nitrogen retention rate and digestive energy were 34.72%, 8.75 MJ/kg respectively in the straw and 41.40%, 9.97 MJ/kg in the plate. 3) When feeding sunflower straw to sheep, there were significant (P<0.05) differences in molar ratios of acetic acid and ammonium nitrogen in rumen fluid. There were no differences in pH, total volatile fatty acids, molar ratio of propionate acid, butyrate, other acids and total nitrogen, urea nitrogen, protein nitrogen in rumen fluid (P>0.05). When feeding sunflower plate to sheep, there were significant (P<0.05) differences in molar ratios of acetic acid, propionate acid, and the ratios of acetic acid to propionate in rumen fluid. There were no differences in pH, total volatile fatty acids, in molar ratios of butyrate, other acids and nitrogen in rumen fluid.