Weight is an important sign reflecting the baby’s growth and development, and is an important basis for judging the nutritional status, etc. Generally speaking, the weight gain of children increases with age, and the younger the age, the faster the weight gain. The weight growth of children does not rise in a straight line, sometimes fast and sometimes slow, which is a physiological phenomenon. A normal full-term baby weighs about 2500 to 3999 grams at birth. In the first 3 months, the baby’s weight gain is 180-200 grams per week, 150-180 grams per week in 4-6 months, 90-120 grams per week in 6-9 months, and 60-90 grams per week in 9-12 months. According to the weight growth multiplier, the baby weighs twice as much at birth at 6 months and about three times as much at 1 year. The formula for calculating the weight of babies at different stages: weight (kg) within 6 months = birth weight + age of months × 0.6, weight (kg) from 7 to 12 months = birth weight + age of months × 0.5, and weight at 1 year is 3 times the weight at birth. The child should be weighed once at 2, 4, 6, 9 and 12 months after birth, and each time the result should be marked on the growth chart and traced as a weight curve, and then the shape and trend of the child’s weight curve should be evaluated objectively. If the child’s weight curve is parallel to the standard weight curve, it indicates a normal growth rate; if the weight curve is flat or downward, it indicates slow growth and the cause should be actively sought.