The invention discloses a positive electrode of a sodium-sulfur battery, in the field of chemical energy storage. The positive electrode comprises a shell and an electrolyte ceramic tube, A ceramic insulating ring protruding in the radial direction is fixed on the top surface of the electrolyte ceramic tube; the bottom of the outer wall of the electrolyte ceramic tube is provided with a buffer layer resisting infiltration of sulfur and sodium polysulfide; the outer side surface of the ceramic insulating ring and the inner side surface of the shell are connected through an L-shaped metal ring, a groove-shaped metal ring and a top metal ring; the L-shaped metal ring is divided into a vertical section and a horizontal section, the top surface of the horizontal section is fixed to the bottom surface of the ceramic insulating ring, and the inner side surface of the vertical section is fixed to the outer side surface of the ceramic insulating ring; the outer side surface of the vertical section is separated away from the inner side surface of the shell and the top surface of the vertical section is higher than that of the ceramic insulating ring; the groove-shaped metal ring is provided with an inner circle groove wall and an outer circle groove wall; the inner circle groove wall is higher than the outer circle groove wall; the outer side surface of the outer circle groove wall is fixed to the inner side surface of the vertical section of the L-shaped metal ring; the top metal ring is connected with the outer side surface of the inner circle groove wall of the groove-shaped metal ring and the inner side surface of the shell.