The height of a five-and-a-half-month-old infant should be around 63cm and the weight should be around 7~7.5kg. Height and weight are indicators that reflect the growth and nutritional status of infants, based on the average birth height (length) of newborns of 50cm, the height of infants 1-6 months = 50 + 2.5 x age in months (cm), the height of infants in more than five months should be around 63cm; the weight formula for (age in months + 9)/2 (kg), the weight of infants in more than five months should be around 7-7.5kg, due to the physique, feeding and other Due to differences in physical condition, feeding and other factors, there may be slight fluctuations. Infants should pay attention to balanced nutrition, dietary hygiene, pay attention to warmth, avoid cold, pay attention to the growth and development of the child, abnormalities in a timely manner to consult the doctor, under the guidance of the treatment.