This experiment was carried out to compare the effects of summer temperature and nitrogen application on carbohydrates and fiber contents in orchardrass stubble grown in the cool summer year, 1980 and in the hot summer year, 1984. For this study, the contents of carbohydrates, neutral detergent fiber (NDF), acid detergent fiber(ADF) and hemicellulose in orchardgrass stubble were investigated. 1. Total water soluble carbohydrates(TSC) in orchardrass stubble were accumulated during the period of cool season and were declined when the weather was hot and dry. The reserve level of those were decreased when a new leaf emerged after the start of plant growth and then were increased as the plant was in full flourish. 2. The reserve of carbohydrate content in orchardgrass stubble was about twice times higher in cool summer year than that in hot summer year, and the reserve rate of carbohydrates showed to be fast in cool summer year. When the nitrogen fertilizer applied, the content of TSC in orchardgrass stubble more lowered but not significantly different(p<0.05). 3. The contents of NDF, ADF and hemicellulose in orchardgrass stubble in cool summer year were not significantly different from those in hot summer year. These contents showed also no significant difference among different levels of nitrogen applications. 4. The relationship of carbohydrate, NDF, ADF and hemicelluose contents according to the levels of nitrogen applications were negatively correlated in cool summer year. But there was no consistency in hot summer year.