In view of the fact that the lack of intelligent fertilization guidance in apple orchards results in imbalanced nutrientsupply and low fertilizer efficiency of fruit trees which may lead to unsatisfactory fruitquality，this article proposed a precisefertilization model for apple trees based on their leaf nutritiondiagnosis.Firstly，a model for estimating the flower number of apple trees based on FCM-Fuzzy Clustering wasestablished.According to the fruit -leaf theory of appletrees，the relationshipbetween flower number and fruit yield was deducted and the target yield of apple trees was estimated.Secondly，the totalfertilization amount of fruit trees was calculated by analyzing the target yield of fruit trees，soil nutrient content，fertilizerutilization rate and fertilizer nutrient content in the nutrient balance method and the growth status，fertilizer requirement characteristics and leaf nutrition diagnosis in the annual growth cycle of apple trees were taken into consideration in order toformulate the fertilization system and establish the fertilizationmodel.Finally，the fertilization model verification test in thedemonstration apple orchards was conducted by means of contrast experiment，and the results of fertilization amount and fruitquality of two control groups werecompared.The results showedthat:(1)The experience guiding fertilization resulted inan obvious change in the big change of fertilizer amount and large fertilizer consumption，while the fertilization model guidingfertilization led to a slight change in the amount of fertilizer application and less fertilizer consumption，and the estimationresult was more accurate.(2)The fruit quality of the orchard with fertilization model guiding fertilization was significantlyimproved compared with that of the orchard with experience guiding fertilization.The weight of single fruit was increased by37 g inaverage，the hardness of fruit was enhanced by 1.7 kg/cm 2，the soluble solid content was increased by2.5%，and thenumber of fruits with more than 60% coloring surface was increased by11.5%.Insummary，the precision fertilization modelin apple orchard based on leaf nutrition diagnosis can improve the fruitquality，reduce the fertilizerwaste，and achieve the scientific fertilization guidance in orchards.