Monitoring the state of RC structures is an essential need to guarantee their performance level, which is both a traditional direction and a new development brought about by advances in other fields. This paper presents an overview of the new technologies in recent years for rebar corrosion monitoring and concrete durability monitoring techniques in reinforced concrete structures, mainly presenting (1) in terms of rebar corrosion monitoring, chemical monitoring methods such as half-cell and natural potential method, polarization resistance technique, current noise assessment method, and physical monitoring techniques such as ultrasonic monitoring method, physical imaging technique, and electromagnetism monitoring technique; (2) in terms of concrete condition monitoring, ultrasonic monitoring, digital imaging technology, damage evaluation index system research and other monitoring technologies based on the deterioration of concrete itself and monitoring technologies based on concrete cracks to assess the state of concrete; (3) in terms of sensors and signal processing technology, fiber optic sensors and other new sensor technologies. In the development of front-end technology in the state perception layer, the integration of human intelligence technology is a trend of future interdisciplinary development.