The apple(Malus domestica B.)is one of the most produced fruits in the world.Since the high quality of fruit is an important characteristic for consumers,much research has focused on developing new techniques to maintain the optimal sensory properties of fruit.A great deal of research has been done on apple final quality in recent years,however few studies have focused on the physiological aspects of apple development,such as photosynthesis,the accumulation of carbohydrates and other primary metabolites,which also play a crucial role in apple final quality.Some important physiological changes and mechanisms related to apple primary metabolism,as well as the effects of agronomic measures(such as fruit thinning)on improving apple fruit quality and meeting consumer demand were discussed,with the aim of accumulating existing information and proposing future research directions.