Abstract: Ketogenic diet(KD),refers to a diet of high-fat,low-carbohydrate and moderate amount of protein. As one of the non-drug treatment methods for refractory epilepsy,KD has been used for nearly 100 years. With the evolution of classic ketogenic diet to medium chain triglyceride diet,modified Atkins diet,and low glycemic index treatment,KD has been applied not only in the treatment of nervous system diseases such as children refractory epilepsy,but also in the prevention and control of other chronic diseases such as diabetes and complications,obesity and related diseases,tumors,as shown in the latest studies. This review aimed to explore KD and its application in the improvement of chronic diseases,by a brief summarization of the possible mechanism of action of KD,and discuss its safety. This study would provide a basis for better understanding and further application of KD.