Carotenoids, vitamin C and flavonoids are mainly enriched in citrus fruits, and the effects of different environmental factors such as light, temperature, pH and humidity on the synthesis of these three nutrients are discussed. Because of its rich nutrients and delicious taste, citrus has become the first choice of fruit in People’s Daily life. Carotenoids are important nutrients and natural pigments in citrus, and their synthesis is affected by light, temperature and pH value. However, this paper does not delve into the effects of different environmental factors on the synthesis of common nutrients in plants, such as water, fructose, and fruit acids, which require further discussion. Through these discussions, this review aims to provide a scientific basis for the cultivation of citrus and other fruits, promote sustainable agricultural production, and provide consumers with more healthy and nutritious fruit choices.