Fatty acid synthase (FASN) is an important biosynthetic enzyme,and it is a key enzyme in tumor lipid production. It plays an important role in catalyzing fatty acid synthesis. FASN is overexpressed in many tumor cells but not in the corresponding normal cells. Accumulating evidence suggests that FASN is a metabolic oncogene playing an important role in tumor growth and survival. The specific metabolic phenotype was originally known as the Warburg effect. Abnormal fatty acid metabolism is related to the survival and invasiveness of cancer cells indicating that abnormal fatty acid metabolism provides the crucial components and energy sources of cancer cells. Its overexpression is associated with the occurrence, evolution, invasion and prognosis of tumors. The expression and activity of FASN in the metabolic pathway of fatty acids were observed in various tumors, and it is closely related to poor prognosis. By down-regulating the expression of these metabolic enzymes or using specific inhibitors, inhibiting the activity of metabolic enzymes can inhibit tumor growth. It is found that FASN inhibitors inhibit tumor recurrence and metastasis. By inhibiting the enzyme activity of FASN, it leads to lipid starvation of tumor cells, thus effectively inhibiting the proliferation of cancer cells, so that it can break away from the vicious cycle and go to apoptosis. Understanding the regulatory mechanism of FASN expression may help developing novel FASN inhibitors and may provide new therapeutic moieties for neoplasms therapy. The role of FASN and FASN inhibitors in tumor cell, is reviewed in this paper.