Abstract: Rad protein is one of the members of the Ras superfamily of guanosine triphosphatases (GTPases) and is a newly discovered small G protein. Rad is expressed in a variety of cells involved in maintaining heart functions, regulating myocardial apoptosis and inhibiting migration of vascular smooth muscle. Abnormal Rad expression is closely related to human tumor development. Rad plays an important role in biology and medicine. This paper reviews recent progress in Rad protein research.