This study was conducted to compare chlorophyll contents, photosynthetic abilities, and ribulose-diphosphate (RuDP) carboxylase activities of Quercus acutissima seedlings grown with and without cotyledons under different light intensities and different nutrient levels. The results obtained in this study were as follows : 1. Chlorophyll contents were not significantly different among the light intensities except for 25% of full sunlight at the last harvest time. 2. RuDP carboxylase activity increased with increasing light intensity. 3. Photosynthetic abilities of seedlings grown under full and 75% of sunlight were significantly higher than that under 25% of full sunlight. 4. RuDP carboxylase activity was more related with chlorophyll a contents(r=0.7921 than chlorophyll b contents(r=0.314). 5. RuDP carboxylase activities of the seedlings received at 1 or 2% addition rates of nutrients under 75% of full sunlight were higher than that at 0.5% addition rates.