1. Sun protection: 71.5% of patients with melasma occurrence and aggravation are related to sunlight, so sun protection is very important for melasma patients. From theoretical research and practical consideration, the use of sun hat or sunscreen has a certain preventive effect on the occurrence of melasma, and the best sun protection measure to prevent melasma is to use sunscreen and sun hat together, which can reduce the risk of melasma. 2.Women using contraceptive ring is a risk factor for melasma, so melasma patients should pay attention to the choice of contraceptive methods. In the survey, it is found that the number of women who take oral contraceptive pills for a long time to achieve the purpose of contraception is getting less and less, but the disease of melasma has not been reduced as a result. Therefore, it can be considered that women who use the ring to contraception have a greater risk of melasma than women who do not take contraceptive measures. 3.Ensure sufficient sleep: Sleep is the protective factor of melasma, and the risk of melasma decreases gradually with the extension of sleep time. Clinical observation shows that some melasma patients are often troubled by sleep, some of them show short sleep time, some have difficulty in falling asleep, easy to wake up after falling asleep, poor sleep quality, and after a period of sleep trouble, facial spots gradually appear. According to traditional Chinese medicine, chloasma can occur in cases of emotional disorders, liver qi stagnation, or kidney qi deficiency, dysregulation of the flush, liver disease and other chronic diseases. After analysis, with good sleep quality as the baseline, those with better sleep quality than those with good sleep treatment are more likely to suffer from chloasma. 4.Good mood: the occurrence and aggravation of melasma and emotion or exertion related patients account for 54.5%, controlling their emotions, being in a relaxed mood and combining work and rest are the problems that melasma patients should pay attention to. 5. Drug allergy and cosmetic allergy are the risk factors of melasma. For patients with sensitive skin, the selection and correct use of cosmetics are more important. 6.The intake of moderate amount of soybean products is a protective factor for melasma. After analysis, only the intake of soybean products has significant difference for melasma disease. Soybean products contain a large amount of isoflavones, which have estrogen-like effects in any body and are called “phytoestrogens”. The moderate intake of soybean products can reduce the risk of melasma, so it can be considered that the moderate consumption of soybean products has a certain effect on the prevention of melasma.