The prevalence of non- alcoholic fatty liver disease( NAFLD) keeps rising worldwide along with the increasing prevalence of metabolic diseases such as obesity,type 2 diabetes,and dyslipidemia. Although most NAFLD patients present with simple steatosis of hepatocytes,some patients progress to non- alcoholic steatohepatitis,liver cirrhosis,and even cancer. In the Western world,NAFLD is the most common cause of elevated liver enzymes,and hence there has been a growing interest in this disease. Given that fat deposition in the liver is the hallmark of NAFLD,we review the roles and the underlying mechanism of disturbed lipid metabolism in the development of NAFLD and suggest that more insights into the pathogenesis of NAFLD will help develop targeted strategies for the prevention and treatment of this disease.