In an attempt of develop composite flours, Korea yam (Dioscorea batatas) was investigated in terms of the physicochemical properties and sensory evaluation with doughnut. Yam had 76.10% of water, 18.63% of carbohydrate, 4.03% of crude protein, 0.27% of fat, 1.02% of ash and 17.20% of starch. Compositions of the free sugar in yam flour were glucose, fructose and sucrose, which of amounts was about 30% respectively. The major free amino acids of yam were Serine, Arginine & Alanine, which consisted of 70.3% of the total free amino acids. Most amino acids of yam were Glutamic acid, Aspartic acid & Arginine which consisted of 47% of total amino acids. As the amount of yam flour in doughnut was increased the oil absorption rate was lower. In the sensory evaluation, control and 10% flour group did not show any significant difference in all category of sensory characteristics.