Pubertal development is generally divided into three periods. Early puberty is characterized by a sudden increase in height, breast development in girls and testicular development in boys, which lasts for two years. Middle puberty is characterized by the first menstruation in girls and spermatorrhea in boys, the gradual development of the sexual organs, and a decrease in the rate of growth in height; middle puberty lasts for two to three years, while in the later period, the growth of boys and girls slows down and the development of the sexual organs reaches the level of adulthood, which lasts for two years. The whole development process of puberty will be relatively long, girls generally 10 years old breast development, 11 years old breasts continue to develop and have pubic hair began to grow, 12 years old reproductive organs will develop, 13 years old nipple pigmentation, menstruation for the first time, 14 years old ovulation, there will be a reproductive function, 15 years old began to change their voices, 17 years old bone development stopped. Pubertal boys generally 11 years old testicular development began, the boy’s testicular development is greater than four milliliters as a sign of puberty, 12 years old scrotum development and pigmentation, penis development, 13 years old prostate activity, pubic hair development, 14 years old testicles and penis rapid development. 15 years old armpit hair growth, voice change, there will be spermatozoa, 16 years old sperm maturity, 17 years old, 18 years old skeletal development stops. There are individual differences in each period, and there is no absolute specific age division. If there is any discomfort or developmental abnormality, it is recommended that the patient go to the hospital in time to clarify the cause of the disease and then be treated under the guidance of the doctor.