Embryonic circuit is a new kind of bio-inspired hardware with the capability of self-diagnosis and self-repair. It can effectively improve the reliability of electronic equipments in complex environment. Self-checking is the premise of embryonic circuit self-repairing and is an important factor of embryonic circuit reliability. It is also one of the key issues in embryonic circuit research. In this paper, the basic concept of self-checking technologies and the status of studies at home and abroad are introduced, and a classification is given. The features of different embryonic circuit self-checking technologies are studied, and the main problems are discussed.A prospect is given for future development of the technologies.