A dark line on the abdomen of a woman is the abdominal white line, which is a line from the umbilicus to the pubic symphysis, and is a normal physiological phenomenon. A dark line on the female abdomen is formed from the umbilicus to the pubic symphysis, which is a normal physiological phenomenon. The color of the abdominal white line is dark or light due to the intersection of the left and right side of the abdominal muscles in the middle part of the hyperpigmentation occurs, and the dark or light color of the line and the individual’s constitution has a certain relationship with the factors, which varies from person to person. A dark line on the female abdomen can also be deepened after pregnancy under the action of estrogen, but due to the different physique of each individual, the depth of the white line will be different, but the white line of the abdomen will increase with the weeks of pregnancy, the color gradually deepened to the late stages of pregnancy due to the growing belly, so that the line is more clear, and will gradually become lighter after delivery. A dark line on a woman’s abdomen is a normal phenomenon, not only for women, but also for men, and does not require special treatment.