Spraying foliar fertilizer on fruit trees timely can achieve the purpose of strong trees, disease resistance and high yield. The method is simple and effective. The technical points are as follows: The suitable period for spraying fertilizer can be sprayed in the whole growing season, but it is better to spray when the fruit tree needs the fertilizer most. As far as fertilizers are concerned, the fruit trees have different growth periods and the demand for fertilizers varies. Before and after budding, leaf spreading and flowering, nitrogenous fertilizer should be sprayed to promote flower bud differentiation and increase fruit setting rate; spraying 0.2%-0.4% boric acid mixed solution at flowering stage can significantly increase the fruit setting rate; Spraying 2%-4% of superphosphate soaking filtrate during the expansion period can increase the sugar content of the fruit. Spraying 0.2%-0.3% potassium dihydrogen phosphate during fruit enlargement period can significantly promote fruit enlargement and improve fruit quality. At the same time can also reduce fruit drop. Spraying Opportunity and Method Spraying efficiency is greatly influenced by wind and temperature. Generally it should be sprayed on a cloudy day without wind. Summer spray fertilizer should be performed before 10 o'clock in the morning or after 4 o'clock in the afternoon. Fertilizer concentration should be properly sprayed according to different growth periods and climatic conditions of the fruit trees and different concentrations of tree species used, the young leaves use a lower concentration, mature trees use a higher concentration.