Focal nodular hyperplasia of the liver is a benign tumor-like lesion with an unknown etiology. Focal nodular hyperplasia of the liver is a rare benign tumor-like lesion characterized by a well defined, firm, non-enveloped, yellowish-brown, substantial mass with star-shaped scarring with radial fibrous segments in the center of the lesion. The possible etiology of this disease mainly includes: congenital vascular malformation, long-term oral contraceptive use, pharmacological liver injury, smoking, etc.. Most patients have no clinical manifestations, and a few may present with symptoms such as right upper abdominal discomfort and right upper abdominal mass. There is no malignant tendency, generally no treatment, a few symptomatic people can be surgically resected. The occurrence of this disease should be timely to the hospital, improve the relevant examination, standardized treatment under the guidance of the doctor.