Microalgae are rich in various nutritional components and active substances， which are regarded as a promising raw material for food with great market potential. Generally， the protein content in microalgae is higher than traditional crops and the protein nutritional value， quality and techno-functional properties are better than crop proteins. Thus， microalgal protein is considered as a kind of supplement or substitute protein for foods. In this paper， the application and research progress of microalgal protein， which can be used as new resource of food ingredient， are mainly expounded from the aspects of protein separation methods， nutritional and physicochemical properties， and their biological activities. Additionally， the development potentials and existing problems of microalgae protein application in foods are also briefly analyzed. This paper is expected to provide references for the scholars who are exploring new food resources and developing future foods.