The invention provides a rotor sealing structure. The rotor sealing structure comprises a rotor, at least one first sealing fin and at least one propping piece, wherein the rotor is provided with at least one side surface groove; each side surface groove is provided with an axis surface, a peripheral surface and an inclined surface; the axis surface is longer than the peripheral surface; the inclined surface is arranged between the axis surface and the peripheral surface; each first sealing fin is arranged between at least one side surface of the rotor and a shell; each propping piece is arranged in the corresponding side surface groove; when the rotor rotates, each propping piece moves to the peripheral surface along the inclined surface due to centrifugal force to prop the corresponding first sealing fin against the shell. The invention further provides a rotor sealing structure which comprises a rotor, at least one first sealing fin and at least one sealing sliding block. Each propping piece moves under the action of the centrifugal force to prop the corresponding first sealing fin against the shell, so that sealing between each first sealing fin and the shell can be strengthened; or each sealing sliding block is propped against the shell under the action of the centrifugal force, so that sealing between the rotor and the shell is strengthened.