The morphological and physiological acclimations to six light conditions were investigated in seedlings of four tree species ( Abies faxoniana, Picea asperata, Acer davidii and Betula albo-sinensis) in subalpine coniferous forests, in Eastern Qinghai-Tibet Plateau, China. Four species are at different successional serals with A. faxoniana as late successional species, P. asperata and A. davidii as mid-late successional species, B. albo-sinensis as a pioneer tree species. The main purpose was to compare the difference in the responses of the plasticity of photosynthetic characteristics to different growth light gradients among the studies species. The growth light regimes designed in this study were 100%, 55%, 40%, 25%, 15% and 7% of the full sun light, respectively. The results were: (1) All seedlings of the four species under the low growth light conditions applied in this study showed decreasing in root collar diameter, relative growth rate (RGR), leaf thickness, root mass ratio (root dry mass/ seedling dry mass), leaf area based photosynthetic capacity and dark respiration rate, light saturation point and light compensation point, but increasing in leaf area per unit mass, above- / under- ground mass, specific stem length (stem length/ stem dry mass), leaf mass rate (leaf mass/ seedling mass) and stem mass rate (stem mass/ seedling mass); (2) Under most light conditions leaf area-based photosynthetic capacity and respiration rates of A. faxoniana were lower than those of P. asperata, while A. davidii had higher values in those parameters when compared to B. albo-sinensis; (3) For P. asperata and B. albo-sinensis seedlings, the relative growth rates (RGRs) were higher than those of A. faxoniana and A. davidii as the growth light regimes increased. However, under the low growth light regimes RGRs of A. faxoniana and A. davidii seedlings were higher than those of the other two species; and (4) The means of phenotypic plasticity index of the eleven morphological and physiological parameters of P. asperata and B. albo-sinensis were higher than those of A. faxoniana and A. davidii, respectively. All of which indicate that A. faxoniana had stronger capacity of acclimation to low light regimes than P. asperata and B. albo-sinensis did, but the capacity of acclimation to high light regimes of the shade-tolerant species was poorer than that of the two early successional seral species. The index of physiological plasticity was higher than that of morphological plasticity, suggesting that morphological plasticity was an important acclimation characteristic for growth light regimes for the four subalpine coniferous tree species. The results in this paper also support the hypothesis that ecophysiological traits of tree species determines their successional status and associated habitats for their seedlings.