The invention discloses a method for preparing syzygium buxifolium root nutritional powder and belongs to the technical field of food processing. Syzygium buxifolium root serves as the raw material, rhizoma imperatae serves as the auxiliary material, and the syzygium buxifolium root and rhizoma imperatae are selected, peeled, diced and pulped; the pulp is subjected to mixing, enzyme treatment, homogenization and spray drying, and the nutritional powder is prepared. The nutritional powder prepared through the method is comprehensive in component, good in instant solubility, pure in flavor and good in taste, more nutrients can be separated out after enzyme treatment, loss of nutrients in the raw materials is reduced, utilization efficiency of the raw materials is improved, and the nutritional powder has the effects of tonifying spleen and removing dampness, relieving asthma and reducing phlegm and the like.