Abstract: Ormosia hosiei is a rare and valuable timber species endemic to China.Investigating the effects of light intensity and fertilization on the growth and functional traits of saplings provides theoretical support for high-quality sapling cultivation and tending techniques.This study examined the effects of light intensities（full sunlight, 50% transmittance and 30% transmittance）and fertilization（5 g urea + 5 g potassium dihydrogen phosphate per plant, 10 g of urea + 10 g potassium dihydrogen phosphate per plant, no fertilization）on 3 year O.hosiei saplings over six months.The results showed that: light intensity and fertilization treatments had no significant effect on the growth of basal stem diameter.However, under 30% light transmittance, fertilization significantly enhanced seedling height growth.Fertilization treatment enhanced the number of leaves, stem height, and biomass under shade conditions; however, it had no significant promoting effect under full sunlight.With increasing shading, chlorophyll content, net photosynthetic rate, transpiration rate, and water use efficiency all decreased to varying degrees.Under 50% light transmittance and full sunlight, a fertilization rate of 10 g per plant significantly improved both the leaf net photosynthetic rate and transpiration rate, while also enhancing water use efficiency.However, under 30% light transmittance, fertilization increased the leaf net photosynthetic rate and transpiration rate but reduced water use efficiency.In conclusion, the 50% light transmission conditions promote seedling height growth, stem length, and biomass.The compensatory effect of fertilization is primarily evident in functional traits and the photosynthetic rate under low light conditions.