The second time after menarche will usually come on schedule, but due to the fact that the gonadal axis of girls is not yet fully developed, so there may be menstruation earlier or later, due to individual differences can not determine the exact time. For women, menstruation will usually come on schedule every month after the onset of menstruation, but because the hypothalamus-pituitary-ovarian axis is not yet fully developed in little girls, it may lead to irregular menstruation and appear to be advanced or pushed back, and the exact time cannot be determined due to individual differences. For little girls, after the first menstruation, we should pay special attention to menstrual hygiene, be diligent in changing sanitary napkins, and during menstruation, we should eat a light diet, pay attention to warmth, pay attention to rest, and don’t do too strenuous exercise, if the menstruation is delayed or advanced more than 1 week, it is recommended that the parents take their children to the gynecology department of regular hospitals as early as possible, and under the guidance of the doctor to actively treat the disease.