The standard height of a 6-month-old baby is 66.7cm and the standard weight is 7.5kg, on which 10% higher or lower is within the normal range. The average length of a normal child at birth is 50cm, and the standard height at 1 year of age is 75cm. Within 1 year after birth, the height growth in the first 3 months is equal to the height growth in the last 9 months. The standard height of a 6-month-old infant is 66.7 cm, and if 10% higher or lower than this is the normal range, the normal height range should be 60.0 cm to 73.4 cm. The formula for calculating the normal weight of infants from 3 to 12 months of age is [age (months) + 9]/2, then the standard weight of 6-month-old infants should be 7.5kg, which can fluctuate 10% higher or lower, and then the normal range should be 6.75~8.25kg. Height and weight are not only related to age, but also related to gender, heredity, nutrition and other factors, and the actual height and weight of children do not increase at an equal rate, so individual differences should be noted in the evaluation, and the so-called “normal values” and “standard values” should not be taken as absolute standards. The so-called “normal values” and “standard values” should not be taken as absolute standards for comparison.