First, the harm of ultraviolet rays on the skin 365 days every day there are ultraviolet rays, even on cloudy days there are ultraviolet rays, only due to the clouds and the ozone layer blocking, so that ultraviolet rays weakened. The main ultraviolet rays that cause skin damage are: long-wave ultraviolet (UVA), medium-wave ultraviolet (UVB) Long-wave ultraviolet (UVA) hazards: year-round existence, strong penetration, can pass through clouds, glass, penetrate the epidermis, directly to the dermis. UVA is mainly caused by photo-aging, that is, damage to the dermal layer of the collagen fibers, leading to sagging and wrinkles in the skin. It also deepens melanin. It produces phototoxic and photosensitizing reactions with food, drugs, perfumes, etc. It can enhance the carcinogenic effect of UVB rays and can also independently induce skin cancer. Medium-wave ultraviolet (UVB) harm: can be clouds, clothing, tinted glass to block most of the UVB lead to skin tanning, pigmentation, sunburn (redness, heat, pain, peeling phenomenon), but also with the induction of skin cancer, it with the increase in the intensity of the sun and increase, so in the summer and autumn seasons of the year, as well as the day of the strongest midday and afternoon, the most vulnerable to these hours of tanning and sunburn. Second, sunscreen from the beginning of children (1) children’s skin stratum corneum thin (about 10% of adults), so the ability to resist ultraviolet radiation is lower than adults. (2) Although children can supplement calcium sun exposure, but only fifteen minutes a day is enough to meet the day’s calcium needs, so excessive sun exposure will only aggravate the damage to the skin (3) ultraviolet radiation caused by skin cancer, is caused by the cumulative damage, ordinary people if the cumulative sun exposure of more than 5,000 hours may cause skin cancer, so from the beginning of the children to reduce the cumulative damage of ultraviolet rays. How to prevent sunburn? (1) When you go out to play umbrellas: but 50% of the ultraviolet rays can pass through the umbrella, and umbrellas can only isolate the UVB (leading to melanin), while the UVA (leading to aging) is almost no effect. (2) try to wear long-sleeved clothes and pants; (3) reasonable use of sunscreen products: 1, go out half an hour before the start with sunscreen products, and should be evenly coated, the thickness of enough 2, do not blindly pursue a high SPF value of sunscreen products, sunscreen products SPF15 can block 95% of the ultraviolet rays, SPF30 of the sunscreen products can block 97% of the ultraviolet rays, while higher SPF value of the sunscreen products on the skin comfortable feeling Relatively lower 3, after going out should be reapplied every 2-3 hours sunscreen products, in order to use the convenience of sunscreen spray can be considered.