We determined the effects of nitrogen (N) loading (35 kg N ha^-1 y^-1) on the needle morphological and photosynthetic traits of 4-year-old seedlings of Japanese larch (Larix kaempferi) under different three light intensities (open, 50% and 20% light) to evaluate how they adjust to low light conditions. Nitrogen deposition in forests has been increasing in East Asia. Although Japanese larch is not native to Hokkaido, northern Japan, this light demanding tree species is now a promising forestation species and reaches to the age of bearing cones for regeneration. Forest gaps affects the success in regeneration. This light-demanding tree is a promising reforestation species, but its success at natural regeneration depends on the availability of light. The net photosynthetic rate at light saturation (P_sat) decreased with increasing shading. Nitrogen addition increased P_sat in unshaded seedlings but not in 50% and 20% light seedlings. Independent of added N, photosynthetic adjustment to the light environment was regulated by the allocation of N between rubisco and light-harvesting proteins. P_sat in full sun was higher with N than without; the difference would be related to changes of stomatal limitation (Ls). With added N, larch seedlings in shade may store extra N in rubisco. Therefore, though Japanese larch is light demanding conifer, at the N level used in this study, shaded Japanese larch seedlings can regenerate in forest floor.