Abstract: The latest progress in applications of magnetic fluid seal in sealing liquids, including blood, sea-waterand petroleum, was tentatively reviewed. The discussionswith specific examples focused on: i) theoretical studies in understanding the complicated magnetic fluid/liquid interface and possible failure mechanisms in the liquids sealing; ii) improved magnetic fluid seal structures available; and iii) the existing problems, such as the poor sealing capacity, low resistance to pressure, low stability and short service life in sealing liquids. Herein, we proposed a novel sealing configuration: a compressed gas-layer, inserted between the magnetic fluid and the sealed liquids, is capable of effectively avoiding their direct contact and turning the sealed liquid medium into sealed gas medium.Simulated with software Fluent, the newly-proposed magnetic fluid seal structure significantly improved the stability at the interface of magnetic fluid and liquids.