The invention relates to a sealing ring and an atomizer in an electronic cigarette. The sealing ring comprises a bottom cover portion, an outer wall portion which is perpendicular to the plane of the bottom cover and is extended axially from the periphery of the bottom cover, an inhalation hole which is through the central of the sealing ring, an inner wall portion which surrounds the inhalation hole, an circular recess which is located between the inner wall and the outer wall, and at least one reflow hole which is through both the bottom cover and the circular recess. If the sealing ring and the atomizer are adopted in the electronic cigarette, a condensed smoke liquid can reflow back into the atomizer via the sealing ring, and can be heated and further atomized again. The invention can improve efficiency in the use of smoke liquid.