The invention discloses an alarming method and device and a breathing machine. The alarming method comprises the steps that a current alarming list is obtained; collision detection processing is conducted on each alarming event in the current alarming list, wherein the collision detection processing includes the operation that other alarming events with alarming conditions including the alarming conditions of detected alarming events are removed from the current alarming list; an alarm signal output device is controlled to output each alarming event retained in the current alarming list.