Infants falling asleep with startle response may be caused by normal nerve reflexes or vitamin D deficiency, which can be dealt with by ensuring that the infant’s sleeping environment is quiet, supplementing vitamin D, and getting proper sun exposure. Since the development of the infant’s nervous system is not perfect, if the infant is stimulated by external bright light or noise during sleep, it is easy to startle. At this time, parents can appropriately pacify the infant, but also to ensure that the sleep environment is quiet. Infants grow and develop rapidly, if they do not pay attention to vitamin D supplementation or insufficient sun exposure, it may lead to vitamin D deficiency. After vitamin D deficiency, infants will have sleep jumping and even hand and foot twitching. Parents should supplement vitamin D for their infants, and often engage in outdoor activities and sunbathing. If the infant often jumps in sleep, or cries a lot after jumping, it is necessary to go to the hospital to find out the cause.