Mobile communication is a resource constrained system, and spectrum is a crucial resource and element. At present, mobile communication has entered the 5G era, and the main spectrum of 5G is 3.5 GHz. The higher the frequency, the weaker the coverage ability, making it difficult to achieve deep coverage in urban areas and wide coverage in rural areas, and the construction cost will also be very high. At present, the mid to low frequency spectrum resources are almost occupied by 3/4G, and it is not possible to fully cultivate these high-quality low-frequency resources. 5G and 3/4G share the mid to low frequency bands. As each network carries users in a dynamic process, if a fixed spectrum allocation strategy is adopted, there will be uneven network busy and idle, which will not fully utilize the utilization of mid to low frequency bands. Dynamic spectrum sharing technology can effectively solve the above problems and improve spectrum utilization. On the premise of introducing the technical principles, this paper introduces the implementation and deployment methods of the technology, and finally proves the effectiveness of the technology through test data.