This paper comprehensively explores the application of Dynamic Spectrum Sharing (DSS) and blockchain technology in 5G and 6G networks, as well as their combined potential. Against the backdrop of the surge in demand for high-bandwidth services in the era of 5G and 6G, the scarcity of wireless spectrum resources and the low utilization rate of traditional static spectrum management have become increasingly severe. DSS allows dynamic sharing of spectrum between different network operators and adjusts the allocation of spectrum in real-time according to user demand, thereby improving the utilization rate of the spectrum. However, DSS brings some challenges related to decentralization, privacy, and security. To address these issues, blockchain has become a potential solution due to its capabilities in transparency, data encryption, immutability, and distributed architecture. This paper first provides a comprehensive overview of the concept, technology, and related challenges of DSS, then reviews the development of blockchain, related technologies, and their working principles. Finally, we discusses and summarizes the application of blockchain in the field of spectrum sharing, and discusses the challenges and trade-offs of implementing technologies such as STBC, FBAA, and BoSDSA, as well as the future development direction of this research field.