Abstract: Taking the old Cinnamomum camphora trees as experiment objectives, the contents of nutritious elements in the tree leaves collected from different localities were comparatively determined, and the tentative standards of nutrient element content in C. camphora tree leaves were proposed. The nutrition diagnosis for the old C. camphora trees was conducted according to these standards, and the trunk injection fertilization with two different types of nutrition solutions to the experiment objectives in weak growth statusl were carried out. The results showed that both of the two different nutrition solutions could effectively promote the nutrient element contents in leaves of the old and weak C. camphora trees in a short time, while the nutrition solution prepared based on the nutrition diagnosis showed better application effect.