For simple estimation of pasture production and nutritive value in relation to height of orchardgrass (Ductylis glomumtu L.), the experiment was carried out in a pasture mixture dominated by orchardgrass. The samples of grasses were harvested at the heights of about 30, 40, 50, 70 and 90 cm at the first harvest under different percentage of 100 (grass coverage): 0 (bareland), 80 : 20, 60 : 40, 40 : 60 and 20 : 80, respectively. As the height of orchardgrass was increased, fresh and dry matter (DM) yield were significantly increased. The regression equation between DM yield (Y) and height (X) was Y=ll. 5390 X- 146.60 (r=O. 9414 * * ). Also the higher bareland, the lower pasture production was observed. As the plant height at the first harvest was increased, the contents of crude (C) protein, C. fat, C. ash and relative feed value were markedly decreased. On the other hand, the contents of C. fiber, NFE, NDF. ADF, cellulose and lignin were significantly increased, respectively. The higher height, the lower DM digestibility was found. The equation between digestibility (Y) and height (X) was Y=- 0.2193 X+ 80.99 (r = - 0.9862**). Considering DM yield, digestibility and crude protein, the optimum height of orchardgrass at the first harvest was 59 to 67crn for better pasture production and nutritive value.