Abstract: The seedling growth, root architecture, root-penetrating of Magnolia denudata Desr. planted in root-pruning bags for three years were compared to that grown in field by root investigation. The result showed: There was no difference in seedlings growth between M. denudata grown in field and planted in root-pruning bags, while the result of root architecture showed difference, the absorption root (root tips diameter ranged from 0—2 mm) and leading root tips (root tips diameter ranged from 0 mm to 2 mm, 2 mm to 5 mm of M.denudata grown in root-pruning bags had more root tips, root surface area, and root volume. M. denudata planted in root-pruning bags have larger root surface area and root volume which was from the containers' wall of 0—14 cm in horizontal direction and from the top of 21—33 cm in vertical direction, while the amount of root tips is 71.5% of all the root tips. The root-pruning bags used for three years have been worn out so that some roots penetrated the wall of bags.The roots penetrating the bags were that with the diameters below 1 mm and more than 10 mm.