Using wrapped pin FLGS-TDP stem flow meter technology, the paper measured the stem flow rate of two magnolia full crown trees with root strength treatment after transplantation. Combined with the automatic meteorological measurement system, the research analyzed the root cut treatment and environmental factors on the tree’s growth. And the influence of stem flow rate. The daily changes of sap flow rate showed a trend of day-high and night-low, and the monthly changes showed a significantly higher trend in summer than in autumn. Compared with the control, the average sap flow rate of transplanted trees was lower than that of untransplanted trees of the same size, ten times the DBH. The root breaking strength of seedlings grows better than that of 6 times the diameter at breast height. Magnolia full-crown seedlings transplanted with ten times the diameter at breast height and root breaking strength are more adaptable; temperature and relative air humidity have the most significant impact on the seedling stalk flow rate after transplantation. In the early stage of transplantation, the management of water and fertilizer, shade management, and thinning of branches and crowns of magnolia are the primary condition to ensure its survival rate.