This experiment was carried out to evaluate the effect of nitrogen fertilization on the rate of growth and the accumulation pattern of total water-soluble carbohydrates and crude proein in orchardgrass cv. potomac before and after winter. Plants were grown in the pots under different levels of nitrogen fertilizer (3㎏, 6㎏ and 10㎏ per 10a) from 21 September, 1979 to 25 April, 1980 at experimental field of Chonnam National University in Kwangju. The resultes obtained were as follows: 1. Plant heights before winter were increased continuously and reached its peak an about December 5 with the average temperature of 5℃ and then decreased. However, plant leaves, tillers and dry matter in the shoots increased until the end of December, below average temperature of 5℃. 2. The total water-soluble carbohydrates (TSC) in the basal tissue before winter accumulated until the end of December, below average temperature of 5℃. The reserved carbohydrates in the basal tissue after winter decreased when new leaf after the start of plant growth emerged and then increased with morphological development. But the content of TSC decreased again after emergence of tiller and then increased. Crude protein content in the basal tissue both before and after winter decreased as plants aged.