The spider web-like red blood on the chest is mostly considered to be caused by spider nevus, the etiology of which is related to physiological factors, cirrhosis, viral hepatitis and so on. Spider nevus is a vascular nevus formed by the expansion of the terminal branches of small arteries in the skin, which is composed of a central small artery and fine blood vessels radiating outward, and its main appearance is that the fine blood vessels extend outward, and its shape resembles that of a spider. It can appear on the trunk, face, and upper chest, and is characterized by spiderweb-like red blood on the chest. Spider nevi can appear in adolescent women due to the large amount of estrogen in the body, and this is a normal phenomenon. This is a normal phenomenon. With age, the estrogen in the body gradually decreases, and the spider nevus can disappear on its own. Spider nevus also exists pathological factors, if the liver function is damaged due to various reasons, it may also induce spider nevus, such as cirrhosis, viral hepatitis, rheumatoid arthritis, Cushing’s syndrome and other diseases. If the patient has a spider web-like red blood on the chest, he can go to the regular hospital and have a relevant examination, so as to clarify the cause of the disease.