An adjustable oral interface (1) adapted to the oral structure of a patient, for use in transmitting negative pressure generated by an oral negative pressure therapy system. The adjustable oral interface (1) comprises: a baffle (100) adapted to be placed between the lips (500) and the incisors (502) of a user； a negative pressure transmitting component (130) connected to the baffle (100)； and a fluid tube in fluid communication between the negative pressure transmitting component (130) and a negative pressure generating source. The negative pressure transmitting component (130) is adapted to be adjustably placed in a space between the tongue (504) and the upper jaw (506) of the user to conform to the contour of the user's upper jaw, thereby making it beneficial for the oral interface (1) to transmit negative pressure to the front and rear end areas of the oral cavity by means of the negative pressure transmitting component (130), and reducing the air space between the tongue (504) and the upper jaw (506).
