The height of a 3.5 year old boy is 89.3cm-112.7cm and his weight is 11.31kg-22.13kg, which is mainly related to congenital genetic factors and acquired factors, and there are differences between individuals. At the age of 3.5 years, children’s height and weight increase in a balanced manner. Height increases by about 5-7cm per year, with a normal range of 89.3cm-112.7cm; weight increases by about 2kg, with a normal range of 11.31kg-22.13kg, and there are differences between individuals. Inborn genetic factors include parents’ height and weight, as well as the height and weight of the baby at the time of birth. If the parents are taller, the child tends to be taller. Acquired factors include nutritional factors, sleep, exercise and other aspects, so there are differences between individuals, but as long as it is in line with the growth curve, basically normal. Therefore, it should be ensured that children can have balanced nutrition, active exercise and sufficient sleep, which is conducive to their growth and development. It is recommended to have regular medical checkups and, if necessary, timely consultation with the Department of Child Health to take targeted treatment.