Girls who menstruate at the age of nine and a half generally do not need treatment. Girls who menstruate earlier than nine years old are considered to be sexually precocious, so there is no need to give special treatment for menstruation at the age of nine and a half. Menstruation is one of the signs of the maturity of the reproductive system, the first time to come is the menarche, the age of the first menstruation is affected by genetic factors, personal constitution, acquired nutrition and so on. With the richness of material life nowadays, children’s nutrition level is also more adequate, the body develops faster, and children’s development has advanced, nine and a half years old menstruation is also a normal phenomenon, no need to be treated. If a girl is nine and a half years old and menstruating, we should patiently explain physiological hygiene knowledge to the girl to reduce the fear of psychology. Teach girls to use hygiene products correctly, change sanitary napkins in time, clean the vulva with water every day, keep the vulva clean and prevent infection.