Abstract: The seedling morphological characteristics and growth dynamics of nine Medicago sativa varieties under shade were studied. The height of Eureka showed significantly less plasticity than other varieties under different levels of shading. All varieties showed a larger morphological plasticity at lower light intensities than at higher intensities: They developed distinctly fewer crown ramus, root nodes, leaves and secondary lateral roots, thinner leaves and taproots at lower intensities. Light intensity had little effect on the taproot length of all varieties. The leaf area of Xinjiangdaye, Alfaking, and Derby showed no obvious difference when other varieties significantly decreased. With decreasing light intensity, both the gross and root biomass allocation significantly decreased while stem and leaf biomass allocation increased. The leaf area ratio significantly increased but the relative growth ratio was significantly reduced with an increase in shading. The different sensitivity to shading of the same organ of different varieties indicated that there were different mechanisms for shade-tolerance among M. sativa varieties.