A medical valve having a valve inside housing and a valve core. The valve core is installed within the housing. The housing is preferably an integrally-formed hollow cylindrical structure. An annular protrusion may be arranged on the outer surface of the housing and a seal ring may be arranged in the center of the inner wall of the housing. The valve core can be made of an elastic material as an integrally-formed cylindrical structure. A lock ring matched with the seal ring of the housing may be arranged on the outer surface of the valve core, and the lock ring can be integrally formed with the valve core. The medical valve inside disclosed by the invention is widely applied to the medical fields such as cushion mask, trachea cannula and laryngeal mask, No metal member is preferably employed, so with magnetic resonance imaging examination without causing interference.