The invention discloses a foliar fertilizer for controlling various physiological diseases of crops. The foliar fertilizer is prepared by urea, calcium superphosphate, potash fertilizer, zinc sulfate, magnesium sulfate, borax, ferrous sulfate, duck feather, carboxymethylcellulose, 35% of sulfuric acid, lime, celangulin, sanguinarine, Azadirachtin and other materials. The foliar fertilizer has full nutrition, high concentration and obvious fertilizer efficiency. The plants grow vigorously after being applied with the foliar fertilizer, the yield of the crops is obviously increased, the quality is better, and the disease and lodging resistance is greatly improved. In addition, the safe and pollution-free botanical pesticides contained such as celangulin, sanguinarine and Azadirachtin can effectively reduce the insect and diseases of the crops, and do not pollute the environment and crops. The foliar fertilizer can be used for controlling the root rot of sweet potato, heart rot of maize, withered tip of maize leaf, maize stripe mosaic disease, cotton red leaf blight, cotton leaf cast, red leaf and yellow leaf cast of mint, yellow leaf dwarf of beans, rice red blight and the like, and the effect is remarkable.