Vascular nevus will not subside by itself. If it is not treated in time, the area of vascular nevus will become larger and larger, which will not only easily cause children's loneliness and inferiority, but also affect the beauty because of vascular nevus, which will bring certain pressure to patients' future life and work. Vascular nevus is caused by vascular malformation. Because it occurs in epidermis and dermis, it often breaks and bleeds after being rubbed or scratched. Vascular nevus is often scratched, resulting in a large amount of bleeding and a long bleeding time. Vascular nevus is very susceptible to infection and ulceration after tumor rupture and bleeding, and finally scar appears.