The invention discloses a solid insulated totally-enclosed ring main unit, which comprises at least a line of leading-in unit and at least a line of leading-out unit, and each line of switch comprises a 3-phase high-voltage vacuum switch unit. The high-voltage vacuum switch consists of a housing fixed inside a box body, and a main switch and an isolator arranged in the housing, wherein, the housing is made of epoxy resin, and a copper joint pin of the main switch and the outside of a busbar connected with the copper joint pin are coated with silicon rubber layers. The ring main unit of the invention adopts a totally enclosed design, which causes the ring main unit to have a smaller volume and compact structure, and to be safe and reliable; the probability of leakage and discharge is low, thus improving the insulation class, and the ring main unit has obvious effect on saving energy and materials; air, moisture, dust and hot and cool air sources are isolated, which effectively retards the corrosion of a power source body, stabilizes the output of source voltage, decreases the times of the device maintenance, reduces expense cost and prolongs the service life of the ring main unit.