The invention relates to the field of agriculture and forestry, particularly to the technical field of pesticides, and more particularly to a plant protecting nutritional agent, a preparation method thereof and amino acid water-miscible fertilizer containing the plant protecting nutritional agent. In order to seek out a novel and environment-friendly pesticide, based on Chinese herbal medicine resources, the plant protecting nutritional agent is disclosed, through combining reactions of szechwan chinaberry fruits, flavescent sophora roots, tobacco leaves, stemona roots, tripterygium wilfordii, stellera chamaejasme, common monkshood mother roots, golden larch bark, silktree albizia bark, saponins, sinapis alba and licorice roots, only the extracting solution of the Chinese herbal medicines is used as the plant protecting nutritional agent, and effects of preventing and treating diseases and insect pests for plants and regulating nutrition are realized. At the same time, the amino acid water-miscible fertilizer containing the plant protecting nutritional agent is safe and environment-friendly, the fertilizer conforms to the use criterion of pollution-free food and organic food and has the advantages that the fertilizer can be repeatedly used without harm to people and livestock or phytotoxicity to the plants, the use cost is low, and the nutritional supplement is completed while insect pests and bacteria are killed.