Abstract: ‍ ‍The joint radar and communication （JRC） aims to realize hardware sharing and spectrum coexistence， and further promote the waveform sharing and function coordination of the two systems. The technological principle of the JRC was summarized. The evolution of the JRC from time and technical dimensions was summarized. Aimed at the resource division of radar and communication， the theoretical principle， research progress and technical characteristics of time-， space-， spectrum-， code-division multiplexing were systematically analyzed. Focused on the shared signal of radar and communication， the shared waveform design and processing method， the technical prospect based on direct sequence spread spectrum， orthogonal frequency division multiplexing， linear frequency modulation， orthogonal time-frequency-space modulation were comprehensively investigated. Finally， in order to effectively avoid the electronics bottleneck problems of high-frequency broad-bandwidth RF applications， the microwave photonics technology and its application in JRC were introduced， the technological vision of microwave photonics-based JRC was clarified. The paper can provide theoretical reference and technical guidance for the development of JRC system with high resources efficiency， high function coordination， high central frequency and broad bandwidth.