There are several reasons that can cause endometriosis as follows: 1, coitus during menstruation, because the mental excitement of coitus, resulting in uterine contraction, coupled with the body’s extrusion, so that the shed endometrial debris, from the uterus along the fallopian tubes into the pelvic cavity or retained in the fallopian tubes, the ovaries, is one of the common causes of endometriosis. 2, because of the abnormal position of the uterus, the normal uterus should be anteriorly tilted forward The normal position of the uterus should be anteriorly inclined and anteriorly flexed, which is favorable for the discharge of menstrual blood. If the position of the uterus is backward tilting, backward flexion, and the degree of backward tilting is very serious, so that the menstrual blood is not discharged, the uterine cavity of the accumulation of menstrual blood when the pressure increases will flow back into the abdominal cavity. Because the menstrual blood is mixed with endometrial debris, causing endometriosis in the abdominal cavity. 3, because of women’s long-term emotional instability, due to endocrine disorders, can also lead to the uterine blood reflux into the abdominal cavity and lead to endometriosis.