Abstract: Self-amplifying RNA (saRNA) vaccines are a new generation of mRNA vaccines. In addition to containing mRNA sequences encoding antigen proteins, saRNA vaccines also have unique self-amplifying elements, so self-amplification of antigen sequences can be performed in vivo. With rapidly developing and maturing in recent years, the application of mRNA vaccine technology in infectious diseases and cancer is increasing. Derived from mRNA vaccine technology, researches of saRNA vaccines in the prevention and treatment of infectious diseases and cancer have been carried out, and the existing research results show its huge development space. saRNA vaccines have a substantial impact on the development and application of mRNA vaccines. In this article, we summarize structural characteristics, biological mechanisms, and delivery principle and materials of saRNA vaccines.