Abstract: Functional foods, being parts of the regular diets, are different from other drugs or dietary supplements.The active ingredients in functional foods play an important role in preventing chronic diseases such as diabetes, cardiovascular diseases and hypertension.With the economic development and people's increased concern on health, the exploitation of functional foods has gradually become one of the hot trends in food industry.In this review, we comprehensively summarized functional foods as follows:the definitions, active ingredients and their functions, products in the market and their development home and abroad.We also addressed problems existed in the market of functional foods, which would provide a reference for the development of the functional food industry.