A newborn full-term baby is about 50cm long, but the individual development of each baby is different, and the situation in the mother is different, influenced by the mother’s intrauterine conditions, such as maternal diseases during pregnancy and the nutritional status of the mother during pregnancy, the environment, emotions and other aspects of influence, infancy is the baby’s first growth spurt, the growth of the first year after birth is about 25cm. In the first year of life, the baby’s growth is about 25cm. The demand for nutrition is relatively high during infancy, and all systems are developing and progressing, but the systems are not fully developed, and the ability to resist infection is weak, so care and nutrition need to be strengthened. Because of the characteristics of development in infancy, it is important to pay attention to the assessment of nutrition and height and weight in infancy, which is important to determine the nutrition of the baby.