During human growth and development, if there are no special changes in the external environment, human growth and development are usually stable and in a distinct trajectory, and their growth and development conditions maintain a limited up and down range in the population they are in, which is a special dynamic and very complex regulatory system, with genetic factors playing a key role. When the child’s body is affected by malnutrition, systemic diseases or endocrine function abnormalities, growth will be delayed, so its growth and development gradually deviates from the normal trajectory, once these factors that hinder growth and development are corrected, the child’s growth and development accelerates again, rapidly approaching and developing towards the original growth trajectory, which is called “catching up with growth This is known as “catch-up growth”. Many important organs and tissues have a “critical growth period”. Disruptions in normal development during this period often become permanent defects or dysfunctions. For example, from mid to late fetal life to 6 months after birth is a critical period of brain tissue growth with a large increase in the number of brain cells. If severe protein-calorie malnutrition, hypoxia and birth injury occur at this time, the cell division and proliferation will be dramatically slowed down; even if various active interventions are carried out later, the catch-up growth cannot be fully realized, the number of brain cells cannot be restored to the proper level, and the intelligence of the affected children will be more seriously affected. Early adolescence is a critical growth period for long bone tissue, and various factors that hinder growth, if acted upon at this stage, will reduce the number of bone cells and hinder bone growth. Without active treatment, the long bones will lose the opportunity to continue growing as the epiphysis of the bone heals, and the child will not be able to reach the level of physical fitness given by his genetic potential.