The purpose of treating children with central precocious puberty with gonadotropin-releasing hormone analogs (GnRha) is both to suppress premature sexual development and to improve the lifelong height of these children, and this is why this drug is superior to other drugs. However, the improvement in lifetime height is not consistent from child to child, i.e., the efficacy is not the same. The difference between lifetime height and predicted height can be considered as the “height gained” after treatment and has been reported to be 3.5-6.5 cm, with a maximum of 10 cm. These differences can be influenced by the size of the bones at the start of treatment, their own genetic growth potential and the duration of treatment, as well as by the age of the bones at the time of discontinuation. If the age at the start of treatment is young, the bone age is significantly advanced, showing a strong maturation momentum, or if the predicted height at the start of treatment is significantly lower than the genetic target height, i.e., the more impaired the growth potential is, the more significant the effect is, and the longer the course of treatment is better than the shorter course of treatment. However, if the bone age at the start of treatment is too old, then the remaining growth potential is small and the final height obtained after treatment is not much. This shows how important early diagnosis and early treatment are to improve the lifelong height of children with precocious puberty.