Abstract: The artificially regenerated 2 years Tilia amurensis seedlings under the canopy of the secondary forest were taken as the research object, and two kinds of light（high light（HL, gap） and low light（LL, canopy）） were set, and four treatments excluding underground competition（fertilization（F）, root cutting（T）, root cutting plus fertilization（T+F）, and control（CK）） were used to determine the morphological characteristics and biomass allocation of Tilia amurensis, and to explore the influence of light and underground competition on artificial regeneration of Tilia amurensis. The results showed that, 1) root cutting and fertilization significantly promoted the seedling height and ground diameter growth of Tilia amurensis, among which T and T+F treatments significantly increased the seedling height and ground diameter growth, while light had no significant effect on the seedling height and ground diameter growth. 2) Biomass and specific leaf weight of Tilia amurensis were significantly affected by the interaction of light and measures to exclude underground competition. Among the 8 treatment combinations, T and T+F treatments under HL significantly promoted the biomass accumulation and specific leaf weight of Tilia amurensis seedlings. The seedling biomass and specific leaf weight of T+F treatment under HL were at the maximum values, followed by T treatment under HL. The seedling biomass of CK treatment under LL was higher than that of CK treatment under HL. 3) T+F and T treatments significantly increased the root length, root surface area and root volume of Tilia amurensis seedlings, and T+F treatment increased more significantly than T treatment. Light had no significant effect on the fine root morphology of Tilia amurensis seedlings. In conclusion, artificially regenerated Tilia amurensis under forest canopy, a moderately shaded light environment under canopy was more suitable for the growth and regeneration of Tilia amurensis. When artificially regenerated Tilia amurensis was carried out in the strong light environment such as forest gap, root cutting or root cutting plus fertilization should be supplemented to reduce the competition of upper layer wood roots for soil resources and promote seedling growth.