1. Development of primary sexual characteristics: the development of reproductive organs. The action of gonadotropin causes the ovaries to enlarge and the follicles to develop and secrete estrogen, which further develops the internal and external reproductive organs. The reproductive organs change from infantile to adult: the pubic mound is elevated, the labia majora and labia minora are thickened and pigmented; the length and width of the vagina increase, the vaginal mucosa thickens and folds appear; the uterus enlarges, especially the body of the uterus, so that the body of the uterus accounts for 2/3 of the total length of the uterus; the fallopian tubes become thicker; the ovaries enlarge and there are follicles of different stages of development in the ovarian cortex, resulting in a slightly uneven surface of the ovaries. At this time, although she is initially fertile, the function of the entire reproductive system is not yet perfect. 2, growth spurt: pubescent girls accelerate physical growth, subcutaneous fat deposition, after the first menstruation growth rate slowed. The typical development sequence of female puberty is: accelerated growth, breast development, pubic hair, and finally the first menstruation. 3. The emergence of secondary sexual characteristics: including higher pitch, breast development, appearance of pubic hair and axillary hair, development of transverse pelvic diameter larger than anterior and posterior diameter, increase of subcutaneous fat in the chest, shoulders and hips, and formation of a female physique. Breast development is the first feature of female secondary sexual characteristics, and is an important sign of female puberty. Generally, when girls are close to 10 years old, their breasts start to develop, and only after that (a few months to a year) do they start to grow pubic hair and axillary hair. 4. Menarche: The first menstrual flow, called menarche, is an important sign of puberty. The first menstruation usually occurs 2.5 years after breast development. Menarche indicates that the ovaries produce enough estrogen to proliferate the endometrium, and when estrogen reaches a certain level and fluctuates significantly, it causes the endometrium to shed and menstruation to occur. At this time, because the positive feedback mechanism of the central system to estrogen is not yet mature, sometimes even though the follicles are mature, they cannot ovulate and anovulatory dysfunctional uterine bleeding occurs, and the menstrual cycle is often irregular at this time, often months, half a year or even longer before the next menstruation. Generally within 3 years of menarche, menstruation evolves from irregular to regular, gradually approaching 28-30 days to menstruate once. 5, psychological changes: adolescence is in a period of accelerated growth and development as well as character rebellion, especially the puberty initiation period, it is the early change process of puberty, the reproductive system begins to develop and gain fertility, is an important milestone of physical, psychological and social transformation. There is a certain difference between biological maturity and social maturity. If social adaptation is difficult, the physiological changes can cause greater psychological changes and predispose to psychological (psychiatric) pathological symptoms, such as irritability, agitation or depression, and even depression. Special attention should be given during this period, and psychological guidance should be given when necessary.