Abstract: Double emulsion(DE)refers to the emulsion droplets contain smaller emulsion system,is mainly used in load functional ingredients. Composed by three different phases and two oil/water interfaces,food grade DE is usually fabricated by stirring apparatuses,high pressure homegenization and membrane emulsification. This paper reviews the instability mechanisms and methods to improve stability of W/O/W DE,and it’s specific applications in food industry and food system. Protection,control release and strengthen effects of functional ingredients can be realized while be loaded by food grade W/O/W DE. However,poor stability,high energy consumption and expensive natural emulsifiers limited the commercial application of food DE. This paper aims to provide some references for understanding the instability mechanisms of food-grade DE,improving its stability and its practical applications in food system,and to expand its application scope in food field. As an emerging emulsion system,double emulsion has an extensive application prospect in food industry.