Abstract: With the technological progress of distributed power generation, energy storage, power electronics and other technologies, the proportion of distributed renewable power generation capacity on the user side in the distribution network will continue to increase, and the demand for distributed energy storage, distributed photovoltaic and DC load power supply will become increasingly apparent. DC distribution has the advantages of two-way flexible and controllable power, fault isolation, fast response speed, etc., and the evolution of the physical form of medium voltage public distribution network to medium voltage DC power supply will become the development direction of the distribution network in the future, but the current cost of medium voltage DC equipment is high, which seriously restricts the promotion and development of DC distribution network. In this paper, aiming at the "double-ended ring" grid of Suzhou medium and low voltage DC distribution and consumption system demonstration project, starting with the medium voltage DC switch, the practicability, economy and technology of different types of switch selection schemes are analyzed, the recommended scheme is given, and the feasibility of the scheme is verified by simulation.