This invention provides an oral interface mainly including a connecting channel, a collapsible chamber and a non-collapsible structure disposed inside the collapsible chamber. The connecting channel communicates between the collapsible chamber and a negative source. When a negative pressure environment is generated inside the collapsible chamber via being pumped by the negative pressure source, the non-collapsible structure supports the collapsible chamber so that there are fluid channels formed inside the collapsible chamber. The air inside a users oral cavity can be pumped out via the fluid channels and the connecting channel. A negative pressure environment is hence formed inside the users oral cavity.
