Sun exposure for babies through glass is ineffective in promoting vitamin production as well as aiding calcium absorption. Under the action of ultraviolet rays in sunlight, 7-dehydrocholesterol in the baby’s body can accelerate the synthesis of vitamin D, which helps to prevent rickets, and vitamin D also promotes the absorption of calcium, which in turn promotes the development of the baby’s bones. However, the intensity of ultraviolet rays from the sunlight separated by glass will be weakened, and the effect on the synthesis of vitamin D and the absorption of calcium will be reduced accordingly. Parents are advised to take their babies outdoors to sunbathe, in the sun at the same time should do a good job of sun protection measures to avoid direct sunlight baby’s eyes, at the same time should pay attention to the control of sunbathing time, and timely hydration to the baby to avoid the baby heat stroke or sunburn.